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The  Cambridge  Manuals  of  Science  and 
Literature 


LINKS   WITH   THE   PAST   IN 
THE   PLANT   WORLD 


CAMBRIDGE    UNIVERSITY   PRESS 

ilontion:    FETTER   LANE,    E.G. 

C.   F.  CLAY,  Manager 


(JFliinbiirflJ} :    loo,  PRINCES  STREET 

ILcntlon:    H.    K.   LEWIS,    136,   GOWER   STREET,   W.C. 

Berlin:   A.  ASHER  AND   CO. 

1Lap>ig:    F.   A.    BROCK HAUS 

f^e'03  Igorfe:   G.   P.    PUTNAxM'S   SONS 

33ombas  anti  (JTalrutta:    MACMILLAN   AND   CO.,   Ltd. 


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Sequoia  magnifica  Knowlton,  in  the  Yellowstone  National  Park. 
(From  a  photograph  kindly  supplied  by  Prof.  Knowlton.)   See  p.  104. 


CambriHgc : 

PRINTED   BY  JOHN    CLAY,    M.A. 
AT  THE   UNIVERSITY   PRESS 

3^ 


^7 


With  the  exception  of  the  coat  of  arms  at 
the  foot^  the  design  on  the  title  page  is  a 
reproduction  of  one  used  by  the  earliest  knonvn 
Cambridge  printer,  John  Siberch,  1 5  2 1 


PREFACE 

1\ /TY  object  in  writing  this  book  is  primarily  to 
call  attention  to  some  of  the  many  questions 
which  are  raised  by  an  enquiry  into  the  relative 
antiquity  of  existing  plants,-  and  to  illustrate  the 
nature  of  the  evidence  afforded  by  the  records  of 
the  rocks.  One  may  agree  with  the  dictum,  *  There 
is  but  one  art — to  omit/  but  to  practise  this  art  is 
often  a  difficult  task.  While  fully  conscious  of  the 
incompleteness  of  the  treatment  of  the  subjects  dealt 
with  in  these  pages,  and  of  defects  in  the  method  of 
presentation,  I  hope  that  I  may  succeed  in  attracting 
some  of  my  readers  who  are  already  interested  in 
living  plants  to  the  study  of  plants  of  former  ages. 

I  am  greatly  indebted  to  my  colleague  Dr  C.  E. 
Moss  for  reading  the  proofs  and  for  many  valuable 


viii  PREFACE 

suggestions.  I  wish  to  thank  Mr  and  Mrs  Clement 
Reid,  Prof.  MacDougal  of  the  Arizona  Desert  Labo- 
ratory, Prof  Campbell  of  Stanford  Universit},  Prof 
F.  H.  Knowlton  of  the  United  States  National 
Museum,  Washington,  Mr  A.  G.  Tansley,  Prof  Yapp, 
and  Mr  W.  R.  Welch  for  photographs  which  they 
have  allowed  me  to  reproduce.  As  on  many  previous 
occasions,  I  am  indebted  to  my  wife  for  contributing 
drawings. 

A.  C.  SEWARD. 

Botany  School,  Cambridge. 
July  1911. 


The  niiinbers  in  brackets  interspersed  in  the  text  refer  to  the 
Bibliography  at  the  end  of  the  volume. 


CONTENTS 

PAGE 

Preface     

vii 

CHAP. 

I. 

Introductory :  the  Longevity  of  Trees,  etc. 

1 

11. 

The  Geographical  Distribution  of  Plants  . 

15 

III. 

The  Geological  Record 

39 

IV. 

Preservation  of  Plants  as  Fossils 

56 

V. 

Ferns ;  their  Distribution  and  Antiquity  . 

71 

VI. 

The  Redwood  and  Mammoth  Trees  of  California 

95 

VII. 

The  Araucaria  family 

106 

VIII. 

The  Maiden  Hair  Tree 

121 

Bibliography 

134 

Index 

139 

Links  loith  the  Past 

ERRATUM 
Page  78.     Omit  lines  5,  6,  and  7,  from  "One"  to  *'but"  inclusive. 


CHAPTER  I 

INTRODUCTORY:  THE   LONGEVITY  OF   TREES,   ETC. 

'  Believe  me  who  have  tried.  Thou  wilt  find  something  more  in 
woods  than  in  books.  Trees  and  rocks  will  teach  what  thou  canst 
not  hear  from  a  master.'     St  Bernard. 

The  recent  publication  in  the  daily  press  of 
instances  of  human  longevity  under  the  heading 
^ Links  with  the  Past'  prompted  a  comparison  between 
the  length  of  time  represented  by  the  duration  of  a 
tree  and  the  lifetime  of  a  human  being.  The  com- 
parison of  single  lives  suggested  the  further  step  of 
contrasting  the  antiquity  of  the  oldest  family-histories 
with  the  remoteness  of  the  period  to  which  it  is 
possible  to  trace  the  ancestry  of  existing  members  of 
the  plant  kingdom. 

My  primary  object  in  these  pages  is  not  to  deal  with 
familiar  cases  of  longevity  in  trees,  but  to  consider 
in  the  first  place  some  of  the  problems  connected  with 
the  origin  of  the  present  British  flora,  and  then  to 
describe  a  few  examples  of  diflerent  types  of  plants 

s.  1 


2  LINKS   WITH  THE   PAST  [CH. 

whose  ancestors  flourished  during  periods  of  the 
earth's  history  long  ages  before  the  advent  of  the 
human  race. 

In  dealing  with  plants  of  former  ages  we  are 
confronted  with  the  difficulty  of  forming  an  adequate 
conception  of  the  length  of  time  embraced  by  geo- 
logical periods  in  comparison  with  the  duration  of 
the  historic  era.  Some  of  the  '  Selections  from  the 
Greek  Papyri'  recently  edited  by  Dr  Milligan 
(Cambridge  1910)  refer  to  common-place  events  in 
terms  familiar  to  us  in  modern  letters  :  we  forget 
the  interval  of  2000  years  which  has  elapsed  since 
they  were  written.  Similarly,  the  close  agreement 
between  existing  plants  and  species  which  lived  in 
remote  epochs  speaks  of  continuity  through  the  ages, 
and  bridges  across  an  extent  of  time  too  great  to 
be  expressed  by  ordinary  standards  of  measurement. 
Terms  of  years  when  extended  beyond  the  limits 
to  which  our  minds  are  accustomed  cease  to  have 
any  definite  meaning.  While  there  is  a  certain 
academic  interest  in  discussions  as  to  the  age 
of  the  earth  as  expressed  in  years,  we  are  utterly 
unable  to  realise  the  significance  of  the  chronology 
employed.  After  speaking  of  the  futility  of  attempting 
to  introduce  chronological  precision  into  periods  so 
recent  as  those  which  come  into  the  purview  of 
archaeologists,  Mr  Rice  Holmes  suggests  a  method 
better  adapted  to  our  powers.     He  says — *  Ascend 


I]  INTRODUCTORY  3 

the  hill  on  which  stands  Dover  Castle,  and  gaze 
upon  Cape  Grisnez,  let  the  waters  beneath  you 
disappear ;  across  the  chalk  that  once  spanned  the 
channel  like  a  bridge  men  walked  from  the  white 
cliff  that  marks  the  horizon  to  where  you  stand. 
No  arithmetical  chronology  can  spur  the  imagination 
to  flights  like  thesed).'  On  the  other  hand,  the 
use  in  some  country  districts  in  Britain  of  spindles 
almost  identical  with  instruments  used  in  spinning 
by  the  ancient  Egyptians,  and  similar  survivals 
described  by  the  author  of  a  book  entitled  The 
Past  in  the  Present(2),  bring-  within  the  range 
of  our  vision  an  early  phase  of  the  historic  era. 
The  rude  implements  still  fashioned  by  the  flint- 
knappers  of  Brandon  in  Suffolk  connect  the  present 
with  the  Palaeolithic  age.  Measured  from  the 
standpoint  of  historic  reckoning,  survivals  from 
prehistoric  days  appeal  to  us  as  persistent  types 
which  have  remained  unchanged  in  a  constantly 
changing  world. 

In  one  of  his  essays  Weismann  quotes  an  old 
German  saying  with  regard  to  comparative  longevity, 
which  asserts  that  *a  wren  lives  three  years,  a  dog 
three  times  as  long  as  a  wren '  and  so  on  in  a  regu- 
larly ascending  series  :  the  life  of  a  deer  is  estimated 
at  three  times  that  of  a  crow  and  an  oak  three  times 
that  of  a  deer,  which  means  that,  computed  on  this 
basis,    an    oak    lives    nearly   20,000    years (3) !     This 

1—2 


4  LINKS  WITH  THE  PAST  [CH. 

fanciful  illustration  of  the  relative  longevity  of  an 

oak  is  the  exi)ression  of  a  truth,  namely  the  superiority 

of  trees  over  animals  in  regard  to  the  duration  of 

life.     As  a  seventeenth-century  translator  of  Pliny's 

Natural  History  writes,  '  In  old  times  trees  were  the 

very  temples   of  the   gods  :    and  according  to  that 

antient  manner,  the  plaine  and  simple  peasants  of 

the  country,  savouring  still  of  antiquity,  do  at  this 

day  consecrate  to  one  God  or  other,  the  goodliest 

and  fairest  trees  that  they  can  meet  withal.'     Oaks 

growing  in  Pliny's  day  in  the  Hercynian  forest  are 

said  to  have  been  there  'ever  since  the  creation  of 

the   world  (4).'     Sir  Joseph    Hooker,   in   an  account 

of  some  Palestine  oaks,  gives  a  drawing  of  a  famous 

tree  at  ^lamre,  known  as  Abraham's  Oak,  which  is 

supposed   to   mark    the    spot   where    the   Patriarch 

pitched    his     tent  (5).      Examples     such     as     these, 

though  of  no  scientific  value,  serve  to  illustrate  the 

well-founded  -belief  in  the  extraordinary  longevity  of 

trees.     In  the  absence  of  evidence  to  the  contrary,  it 

would  be  rash  to  deny  the  possibility  that  \yilliam 

the  Conqueror's  Oak  in  Windsor  Forest,  described 

by   Loudon    in    his    Arhoi'etmn    Brltannicimi    and 

mentioned  by  later  writers,  may  be  a  survival  from 

the  reign  of  the  king  whose  name  it  bears.    Although 

it  is  seldom  possible  to  state  with  confidence  the 

exact  age  of  old  oaks  and  yews  famed  for  length  of 

days,  there   can   be  no  doubt  as  to  the  enormous 


I]  INTRODUCTORY  5 

antiquity  of  many  of  our  trees  whose  years  are 
^sacred  with  many  a  mystery.'  The  section  of  a 
trunk  of  one  of  the  mammoth  trees  of  California 
(Sequoia  gigantea)  exhibited  in  the  Natural  History 
department  of  the  British  Museum,  shows  on  its 
polished  surface  1335  concentric  rings  denoting 
successive  increments  of  wood  produced  by  the 
activity  of  a  cylinder  of  cells  situated  between  the 
hard  woody  tissue  and  the  bark.  It  is  generally 
assumed  that  each  year  a  tree  produces  a  single 
ring,  though,  as  is  well  known,  an  estimate  of  age 
calculated  on  this  assumption  cannot  be  regarded  as 
more  than  an  approximation  to  the  truth.  If  this 
giant  tree,  which  was  felled  in  1890,  was  then  1335 
years  old,  it  had  already  reached  an  age  of  over  two 
centuries  when  Charlemagne  was  crowned  Emperor 
at  Rome.  The  concentric  rings  on  a  tree  trunk  owe 
their  existence  to  certain  structural  differences  be- 
tween the  wood  formed  in  the  spring  and  in  the  late 
summer.  In  Sequoia,  as  in  other  members  of  the 
great  class  of  cone-bearing  trees,  the  wood  is  com- 
posed of  comparatively  narrow  elements  which  serve 
to  carry  water  from  the  roots  to  the  branches  and 
leaves.  As  spring  succeeds  winter  the  inactivity 
of  the  plant-machine  is  followed  by  a  period  of 
energetic  life  ;  opening  buds  and  elongating  shoots 
create  a  demand  for  a  plentiful  supply  of  ascending- 
sap,  and  in  response  to  this  the  tree  produces  a  fresh 


6  LINKS   WITH  THE   PAST  [CH. 

cylinder  of  wood  composed  of  relatively  wide  con- 
ducting tubes.  After  the  first  rush  of  life  is  succeeded 
by  a  phase  of  more  uniform  and  gentler  activity,  the 
demand  for  water  becomes  less  exacting  and  the 
wood  which  is  formed  during  the  rest  of  the  growing 
season  consists  of  narrower  water-pipes.  A  period  of 
rest  ensues,  until  in  the  following  spring  new  layers 
of  larger  tubes  are  laid  down  in  juxtaposition  to  the 
narrower  elements  of  the  latest  phase  of  the  preceding 
summer.  This  alternation  of  larger  and  smaller 
tubes  produces  the  appearance  of  concentric  rings  on 
a  cross-section  of  a  tree.  It  is  not  the  pause  in  the 
active  life  of  the  plant  which  is  responsible  for  the 
effect  of  rings,  but  the  fact  that  the  wood  produced 
immediately  before  and  immediately  after  the  pause 
is  not  structurally  identical.  In  trees  grown  under 
the  more  uniform  conditions  of  certain  tropical 
regions,  the  annual  rings  are  either  feebly  developed  or 
absent ;  for  example,  in  some  Indian  oaks  the  wood 
shows  no  concentric  rings  of  growth. 

Stated  in  general  terms,  rings  of  growth  in  the 
wood  of  a  tree  are  the  expression  of  a  power  possessed 
by  the  plant  of  regulating  the  structure  of  its  com- 
ponent elements  in  response  to  the  varying  nature  of 
the  external  stimuli.  In  certain  circumstances,  for 
example  after  the  destruction  of  the  young  buds  by 
caterpillars,  the  tree  makes  a  special  effort  to  repair 
the  loss  by  producing  a  new  set  of  shoots.     This  may 


I]  INTRODUCTORY  7 

be  recorded  by  the  occurrence  of  two  concentric  rings 
in  one  season.  An  extreme  instance  of  departure 
from  the  normal  has  recently  been  described (6)  in 
which  a  tree  of  Tkeobroma  cacao  (the  cocoa  tree), 
planted  in  Ceylon  in  the  summer  of  1893  and  felled 
in  January  1901,  after  a  life  of  just  over  7  years,  was 
found  to  have  22  rings  in  its  stem.  In  this  case  the 
tree  shed  its  leaves  three  times  a  year,  and  each  break 
in  the  uniformity  of  its  vital  activities  was  registered 
by  the  apposition  of  Avhat  under  ordinary  conditions 
are  spoken  of  as  spring  and  late-summer  wood. 
At  Aden  trees  stated  by  natives  to  be  very  old 
showed  only  five  or  six  rings  of  wood,  a  fact  connected 
with  the  almost  complete  lack  of  rain  and  with  the 
uniform  conditions  of  existence. 

The  degree  of  accuracy  to  be  allowed  to  estimates 
of  age  founded  on  the  number  of  'annual'  rings  is, 
however,  of  secondary  importance  in  comparison 
with  the  enormously  greater  hold  on  life  possessed 
by  trees  as  contrasted  with  the  higher  animals.  Early 
in  the  nineteenth  century  the  Swiss  botanist  A.  P. 
de  Candolle  expressed  the  opinion  that  trees  do  not 
die  from  senile  decay,  but  only  as  the  result  of  injury 
or  disease.  Trees  are  constructed  on  a  plan  funda- 
mentally diflferent  from  that  underlying  the  structure 
of  the  highly  complex  human  organism,  and  are  thus 
endowed  with  a  sort  of  potential  immortality.  It  has 
been  suggested  that  some  of  the  large  corals  in  the 


8  LINKS  WITH  THE  PAST  [CH. 

Red  Sea  which  are  still  tenanted  by  living  polyps 
may  have  been  growing  in  the  days  of  the  Pharaohs. 
The  coral  polyp  represents  the  growing  portion  of  a 
lifeless  mass  of  rock  which  is  constantly  extended  by 
the  activity  of  the  organism  at  the  summit  of  each 
branch.  Between  a  coral-reef  and  a  tree  there  are 
many  essential  differences,  but  a  rough  analogy  may 
be  recognised.  A  tree,  unlike  the  higher  animals, 
does  not  reach  a  stage  at  which  the  whole  of  its 
substance  attains  a  condition  of  permanence  and 
fixity.  It  consists  of  a  complex  branching-system 
in  which  each  shoot  increases  in  length  by  virtue 
of  the  youthful  vigour  of  its  apex  :  to  a  large  extent 
the  tree  as  a  whole  consists  of  lifeless  material  in- 
capable of  further  growth,  as  is  the  case  of  the  older 
portions  of  a  coral-reef ;  but  the  regular  increase  in 
girth  of  the  trunk  and  its  branches  demonstrates  that 
this  comparison  is  only  partially  true,  and  that  the 
power  of  growth  in  a  tree  is  not  confined  to  the 
extremities  of  the  youngest  shoots.  The  tip  of  every 
twig  is  composed  of  minute  cells  endowed  with  a 
potentiality  of  development  like  that  which  charac- 
terises the  embryonic  tissues  of  a  seedling  just 
emerged  from  the  seed.  In  the  course  of  its  growth, 
each  branch,  by  means  of  its  living  and  dividing- 
cells,  contributes  to  the  several  parts  of  the  complex 
mechanism  of  the  tree.  While  the  greater  number 
of  cells  acquire  a  permanent   form    and   lose   the 


i]  INTRODUCTORY  9 

power  of  further  development,  there  remains  a  cy- 
linder of  cells  endowed  with  perpetual  youth.  This 
cylinder  of  living  cells,  known  as  the  cambium,  extends 
between  the  wood  and  bark  from  one  end  of  the  tree 
to  the  other :  by  its  periodic  activity  it  adds  new  layers 
of  tissue  each  year  and  thus,  by  increasing  the  amount 
of  conducting  tubes  for  the  transport  of  water  and 
for  the  distribution  of  elaborated  food,  it  enables  the 
tree  to  respond  to  the  increasing  demands  which 
are  the  necessary  accompaniment  of  increasing  size. 
It  has  already  been  pointed  out  that  in  the  spring 
when  the  sap  flows  most  vigorously  the  cambial 
cylinder  produces  larger  tubes,  and  afterwards  when 
the  tree  settles  down  to  its  normal  life,  these  are 
succeeded  by  narrower  and  stronger  tubes.  These 
later  formed  elements  serve  also  an  important  me- 
chanical purpose  ;  by  the  strength  of  their  walls  they 
increase  the  supporting  power  of  the  tree  and  enable 
it  to  sustain  the  added  burden  of  the  annual  increase 
in  the  weight  and  extent  of  its  spreading  branches. 
It  is  the  persistence  of  permanently  juvenile  tissue 
in  certain  regions  of  a  tree,  together  with  the  re- 
markable power  of  repairing  injuries  and  shedding 
effete  parts,  that  constitute  some  of  the  most  striking 
contrasts  between  the  higher  animals  and  plants. 
The  embryo  oak  in  the  earlier  stages  of  development 
consists  entirely  of  actively  growing  cells  ;  by  degrees 
differentiation  of  the  embryonic  tissues  results  in  the 


10  LINKS  WITH  THE   PAST  [ch. 

localisation  of  regions  of  cell-prodnction  at  the  tips 
of  the  elongating  stem  and  root.  These  apical  groups 
of  cells  are,  in  fact,  portions  of  the  embryonic  organism 
Avhich  persist  so  long  as  the  plant  lives.  This  con- 
tinuity between  the  growing  tip  of  an  old  oak  stem 
and  the  cells  of  the  undifferentiated  embryo  affords 
one  of  the  most  remarkable  examples  in  nature  of 
a  link  between  the  past  and  the  present. 

If  we  pass  beyond  the  stretch  of  time  represented 
by  the  life  of  a  single  tree,  a  few  successive  genera- 
tions suffice  to  carry  our  retrospect  back  to  the  days 
when  forests  of  oaks,  birches,  and  other  trees  im- 
peded the  progress  of  the  Roman  invaders,  and,  a 
stage  farther  back,  to  the  age  of  Neolithic  man  whose 
remains  are  occasionally  found  in  our  heaths  and 
moors  and  in  the  submerged  forests  round  our  coast. 
The  blocks  of  oak  and  beech,  some  of  Avhich  are  as 
sound  as  when  first  felled,  recently  discovered  below 
the  foundations  of  parts  of  Winchester  Cathedral  con- 
structed at  the  end  of  the  twelfth  or  in  the  opening 
years  of  the  thirteenth  century,  are  relics  of  Xorman 
forests.  In  the  course  of  some  excavations  at  Brigg  in 
Lincolnshire  in  188G  a  dug-out  boat  was  found  nearly 
50  feet  long  and  from  4  to  5  feet  in  breadth.  The  stem 
of  the  oak  from  which  the  canoe  had  been  fashioned 
shows  no  sign  of  branching  for  a  length  of  over  40 
feet,  a  fact  which  points  to  the  growth  of  the  tree 
in   a  forest  where   the   race  for   liaht  induced   the 


I]  INTRODUCTORY  11 

development  of  clean  columnar  stems.  The  Brigg 
'dug-out,'  now  in  the  Hull  Museum,  Avas  discovered  in 
an  old  alluvial  valley  of  the  Ancholme  river,  formerly 
connected  with  the  Humber,  and  it  may  be  that 
it  was  used  by  Neolithic  man  as  a  ferry  for  river- 
service  (7). 

From  the  period  claimed  by  archaeologists  we 
pass  by  gradual  stages  into  the  domain  of  the 
geologist.  As  Huxley  wrote,  'when  even  the  dim 
light  of  Archaeology  fades,  there  yet  remains  Palae- 
ontology, which... has  brought  to  daylight  once  more 
the  exuvia  of  ancient  populations,  whose  world  was 
not  our  world,  who  have  been  buried  in  river  beds 
immemorially  dry,  or  carried  by  the  rush  of  waters 
into  caves,  inaccessible  to  inundation  since  the  dawn 
of  tradition (8).'  The  length  of  time  represented  by 
a  succession  of  long-lived  individuals  of  the  same 
species  becomes  enormously  extended  when  we  pass 
to  the  history  of  families,  and  disinter  from  the 
sediments  of  other  ages  the  remains  of  extinct  types. 
As  we  descend  the  geological  series  familiar  types 
gradually  disappear,  and  through  a  succession  of 
changing  floras  we  penetrate  to  the  fragmentary 
records  contained  in  the  older  rocks  until  the  absence 
of  documents  sets  a  limit  to  our  quest. 

The  Scots  pine  shares  with  the  oak,  the  beech, 
the  aspen,  the  yew,  and  several  other  trees  the  right 
to  be  included  in  the  native  flora  of  Britain.     In  the 


12 


LINKS  WITH  THE  PAST 


[CH. 


peat-beds  of  Scotland  even  up  to  3000  feet  above 
sea-level  the  stumps  of  pines  occur  in  abundance, 
and  in  many  places  recent  researches  have  revealed 
the  occurrence  of  successive  forests  of  pines,  oaks, 
and   spruces   separated   from    one   another   by   the 


Fig.   1.     Piniis  sylvestris  Linn,  in  the  Black  Wood  of  Rannoch. 
(Photograph  by  Mr  A.  G.  Tansley.) 

accumulations  of  swampy  vegetation  O).  The  spruce 
fir  has  long-  ceased  to  be  a  member  of  the  British 
flora,  but  in  a  few  localities  in  the  Scottish  High- 
lands patches  of  primeval  pine  forests  remain.     The 


I]  INTRODUCTORY  13 

accompanying  photograph  (Fig.  1),  taken  by  my  friend 
Mr  A.  G.  Tansley,  in  the  Black  Wood  of  Rannoch  in 
north-west  Perthshire,  shows  a  few  trees  of  Plnus 
si/lvestris  growing  in  their  native  soil :  the  form  of 
the  older  tree  {A)  suggests  comparison  with  that  of 
a  well-grown  beech  such  as  we  are  familiar  with 
in  English  plantations.  This  spreading  dome-shaped 
habit  seems  to  be  a  peculiarity  of  the  Highland  tree, 
and  is  one  of  the  characters  which  have  led  some 
botanists  to  regard  it  as  a  variety  (Pinns  sylvestris 
var.  scotica)  of  the  ordinary  Scots  pine.  Though  it 
is  doubtful  if  any  relics  of  primeval  pine  woods  are 
left  in  England,  abundant  evidence  of  the  former 
existence  of  the  Scots  pine  is  afforded  by  the  sub- 
merged forests  exposed  at  low-tide  on  many  parts  of 
the  English  and  Welsh  coasts  and  at  the  base  of 
some  of  the  English  peat  moors.  During  the  con- 
struction of  the  Barry  docks  on  the  north  coast  of 
the  Bristol  Channel  a  few  years  ago,  the  exposed 
sections  of  peat  and  forest  beds  were  investigated  by 
Dr  Strahan  and  by  Mr  Clement  Reid.  There  is 
evidence  of  a  subsidence  of  the  land  to  an  extent  of 
55  feet  since  the  formation  of  the  lower  peat-beds 
containing  oak,  hazel,  willow,  and  other  trees.  The 
pine,  unknown  in  Wales  during  the  historic  period, 
was  recognised  in  the  Barry  cutting.  The  occurrence 
of  a  polished  flint  implement  assigns  a  date  to  the 
uppermost  portion  of  this  old  land-surface  do). 


14  LINKS  WITH  THE   PAST  [ch.  i 

It  is  impossible  within  the  limits  of  a  small  volume 
to  discuss  in  detail  the  evidence  furnished  by  the 
records  of  the  rocks  as  to  the  relative  anti(iuity  of 
the  different  constituents  of  the  present  vegetation 
of  Britain.  In  later  chapters  a  few  selected  plants 
are  described  which  are  pre-eminently  ancient  types. 
Before  passing  to  the  consideration  of  the  data  on 
which  the  geological  history  of  plants  is  based,  brief 
reference  may  be  made  to  one  of  the  most  interesting 
and  difficult  problems  of  botanical  research,  namely 
the  history  of  the  British  flora. 


CHAPTER  II 

THE   GEOGRAPHICAL   DISTRIBUTION   OF   PLANTS 

*  No  siaeculation  is  idle  or  fruitless  that  is  not  opposed  to  truth 
or  to  probability,  and  which,  whilst  it  co-ordinates  a  body  of  well 
established  facts,  does  so  without  violence  to  nature,  and  with  a  due 
regard  to  the  possible  results  of  future  discoveries.' 

Sir  Joseph  Hooker. 

In  the  vegetation  of  the  British  Isles  the  leading 
role  is  played  by  that  large  group  to  which  the  term 
Flowering  Plants  is  frequently  applied.  This  group, 
including  the  two  sub-divisions  Dicotyledons  and 
Monocotyledons,  is  known  by  the  name  xAngiosperms, 
a  designation  denoting  the  important  fact  that  the 
seeds  are  developed  in  an  ovary  or  protective  seed- 
case  (dyyelov,  a  vessel  or  box).  The  fact  that  these 
highly  elaborated  products  of  development  made 
their  appearance,  so  far  as  we  know,  at  a  compara- 
tively late  stage  in  the  history  of  the  plant-world, 
att'ests  their  efficiency  as  a  class  and  demonstrates 
the  rapidity  with  which  they  have  overspread  the 
surface  of  the  earth  as  successful  competitors   in 


16  LINKS  WITH   THE   PAST  [ch. 

the  struggle  for  existence.  As  Darwin  wrote  in  a 
letter  to  Sir  Joseph  Hooker  in  1881,  'Nothing  is 
more  extraordinary  in  the  history  of  the  vegetable 
kingdom,  as  it  seems  to  me,  than  the  apparently 
very  sudden  or  abrupt  development  of  the  higher 
plants(ii).'  In  another  letter  (1879)  to  the  same  friend 
we  read,  'The  rapid  development  as  far  as  we  can 
judge  of  all  the  higher  plants  within  recent  geological 
times  is  an  abominable  mystery (12).'  Making  allow- 
ance for  the  probability,  or  indeed  certainty,  that 
the  imperfection  of  the  geological  record  tends  to 
exaggerate  the  apparent  suddenness  of  the  ap- 
pearance of  this  vigorous  class,  and  allowing  for 
the  fact  that  our  knowledge  of  the  records  of 
the  rocks  in  which  the  highest  plants  first  occur 
is  very  incomplete,  we  cannot  escape  from  the 
conclusion  that  this  recently  evolved  group  spread 
with  amazing  rapidity.  Various  reasons  may  be 
suggested  in  explanation  of  the  dominant  position 
Avhich  the  Angiosperms  hold  in  the  floras  of  the 
world.  As  an  instance  of  their  rapid  increase  during 
the  Cretaceous  epoch  ^,  the  period  which  has  furnished 
the  earliest  satisfactory  records  of  Flowering  Plants, 
the  following  statement  by  an  American  writer  may 
be  quoted : — '  The  rapidity  with  which  it  [/.e.  the 
group  of  Flowering  Plants]  advanced,  conquering  or 

1  For  the  position  of  the  Cretaceous  and  other  systems  in  the 
geological  series,  see  the  table  on  page  42. 


n]         GEOGRAPHICAL  DISTRIBUTION  17 

supplanting  all  rivals,  may  be  better  understood 
when  we  remember  that  it  forms  85  7o  ^f  the  flora 
of  the  Dakota  group '  ;  that  is  a  series  of  sedimentary 
rocks  in  Dakota  referred  by  geologists  to  the  middle 
of  the  Cretaceous  period  (is).  In  the  Wealden  rocks 
of  England,  which  are  rich  in  the  remains  of  Lower 
Cretaceous  plants,  no  undoubted  Flowering  Plant 
has  so  far  been  found. 

The  more  efficient  protection  of  the  ovules,  the 
germs  which,  after  fertilisation,  become  the  seeds, 
the  extraordinary  variety  in  the  floral  mechanisms 
for  assisting  cross-pollination,  the  arrangements  for 
nursing  the  embryo,  and  the  structural  features  of 
the  wood  in  relation  both  to  rapid  transport  of  water 
and  to  the  storage  of  food,  are  factors  which  have 
pi'obably  contributed  to  the  success  of  the  Angio- 
sperms.  The  degree  of  weight  to  assign  to  each 
contributing  cause  cannot  as  yet  be  satisfactorily 
determined,  but  the  general  question  raised  by  the 
recent  origin  of  these  latest  products  of  evolution 
offers  a  promising  field  for  work.  While  admitting 
our  inability  at  present  to  do  more  than  suggest 
possibilities,  we  may  encourage  research  by  specula- 
tion. 

The  members  of  the  Vegetable  Kingdom  placed 
next  to  the  Flowering  Plants  are  the  Gymnos perms 
or  naked-seeded  {yv/iv6<;,  naked)  plants,  including 
(i)  the  Conifers,  e.g.  pines,  firs,  larches,  the  yew,  etc., 

s.  2 


18  LINKS  WITH  THE  PAST  [CH. 

(ii)  a  small  group  of  plants  known  as  the  Cycads, 
whose  existing  members,  now  almost  confined  to 
a  few  tropical  regions,  are  the  descendants  of  a 
vigorous  race  represented  by  many  species  in  the 
floras  of  the  Mesozoic  epoch.  A  third  sub-division 
of  the  Gymnosperms,  the  Ginkgoales,  is  represented 
by  a  single  survivor,  which  is  described  in  a  later 
chapter  as  one  of  the  most  remarkable  links  with  the 
past  in  the  plant  kingdom. 

The  Gymnosperms  are  geologically  very  much 
older  than  the  Angiosperms.  Members  of  this  class 
played  a  prominent  part  in  the  vegetation  of  the 
Coal  age  and  it  is  certain  that  they  existed  in  the 
still  older  Devonian  period.  The  only  other  group 
to  which  reference  is  made  in  later  chapters  is  that 
of  the  Ferns,  one  of  the  sub-divisions  of  a  large  class 
known  as  the  Vascular  Cryptogams  or  Pteridophyta. 
These  plants,  like  the  Gymnosperms,  are  represented 
in  the  oldest  floras  of  which  recognisable  remains 
have  been  preserved.  The  main  groups  of  the 
vegetable  kingdom,  founded  on  existing  plants,  are 
distinguished  by  well-defined  differences  ;  they  are 
comparable  with  separate  twigs  of  a  tree  springing 
from  larger  branches  and  these  again  uniting  below 
in  a  common  trunk.  The  vegetation  of  to-day  re- 
presents only  the  terminal  portions  of  the  upper 
branches.  As  we  descend  the  geological  series, 
records   of  extinct   types   are   found   which   enable 


II]         GEOGRAPHICAL  DISTRIBUTION  19 

us  either  to  trace  the  separate  branches  to  a  common 
origin  or  to  recognise  a  convergence  towards  a 
common  stock.  Were  a  botanist  to  find  himself  in 
a  forest  of  the  Coal  age  he  would  experience  great 
difficulty  in  assigning  some  of  the  plants  to  their 
s}  stematic  position :  characters  now  regarded  as 
distinguishing  features  of  distinct  groups  would  be 
met  with  in  combination  in  a  single  individual.  It 
is  by  the  discovery  of  such  generalised  types,  which 
serve  as  finger-posts  pointing  the  way  to  lines  of 
evolution,  that  the  student  of  pre-existing  plants  has 
been  able  to  throw  light  on  the  relative  antiquity  of 
existing  forms,  and  to  trace  towards  a  common 
ancestry  plants  which  now  show  but  little  indication 
of  consanguinity. 

Confining  our  attention  to  the  dominant  group  of 
plants  in  the  British  flora,  namely  the  Flowering 
Plants,  we  may  profitably  consider  the  question, 
though  we  cannot  satisfactorily  answer  it, — which 
members  of  this  group  are  entitled  to  be  regarded 
as  the  most  ancient  inhabitants  ?  The  past  history 
of  our  native  plants,  and  their  geographical  range, 
not  only  in  the  British  Isles  but  on  the  Continent 
of  Europe,  are  subjects  well  worthy  of  the  attention 
of  field-botanists  whose  interests  are  apt  to  be 
confined  within  too  narrow  bounds.  There  are 
numerous  problems  relating  to  the  composition  of 
the  present  vegetation  of  Britain  which  might   be 

2—2 


20  LINKS   WITH  THE   PAST  [CH. 

discussed  in  reference  to  the  relative  antiquity  of 
plants  ;  but  in  a  single  chapter  it  is  impossible  to  do 
more  than  call  attention  to  certain  considerations 
which  are  frequently  overlooked  by  students  of 
British  species. 

It  is  customary  to  speak  of  the  British  flora  as 
consisting  for  the  most  part  of  species  introduced 
into  this  country  by  natural  means,  while  some 
plants  owe  their  introduction  to  human  agency  or 
are  'escapes'  from  cultivation.  It  is  by  no  means 
an  easy  task  in  some  instances  to  decide  whether  a 
species  is  native  or  introduced,  but  in  some  cases, 
a  few  of  which  are  mentioned,  there  is  no  doubt  as  to 
the  alien  nature  of  the  plants.  The  term  'native' 
needs  a  word  of  explanation.  It  is  not  intended  to 
convey  the  idea  that  a  plant  so  designated  came  into 
existence  on  British  soil  and  spread  thence  to  other 
regions ;  but  by  native  species  we  mean  such  as  have 
reached  this  country  by  migration  from  other  lands, 
or  it  may  be  in  some  instances  have  actually  origin- 
ated in  this  part  of  Europe.  One  of  the  best  known 
aliens  in  Britain  is  the  American  water-weed,  Elodea 
cmiadensis  {OY  Anacharis  alsinastrmn),  which  was 
discovered  about  sixty  years  ago  in  a  canal  near 
Market  Harborough  in  Leicestershire (u).  In  all  pro- 
bability this  North  American  species  was  introduced 
into  England  with  timber.  Once  established,  it 
spread  through  the  waterways  with  alarming  rapidity 


II]  GEOGRAPHICAL   DISTRIBUTION  21 

and  became  a  serious  pest.  Elodea  affords  an  admir- 
able instance  of  the  serious  interference  with  the 
balance  of  Nature  by  the  introduction  of  a  new 
competitor  into  an  environment  conducive  to 
vigorous  development.  Another  foreign  water-plant, 
Naias  graminea,  for  the  importation  of  which 
Egyptian  cotton  may  be  responsible,  has  been 
recorded  from  the  Reddish  canal  near  Manchesterds). 
This  African  and  Asiatic  species  occurs  in  Europe  only 
as  a  colonist ;  it  is  said  to  have  been  introduced  into 
Italy  with  East  Indian  rice.  A  more  recent  case  of  alien 
immigration  due  to  unintentional  human  agency  is 
that  of  Potamogeton  ^yennsglvanicus,  a  pond- weed  of 
Canada,  the  United  States,  Jamaica,  and  elsewhere. 
Specimens  of  this  species  were  first  noticed  in  1907 
in  a  canal  near  Halifax  close  to  the  effluent  from 
a  cotton  mill.  Since  its  discovery  the  plant  has 
slightly  extended  its  range.  It  is  suggested  by 
Mr  Bennett,  who  first  identified  the  alien,  that  its 
fruits  were  brought  to  this  country  in  goods  from 
the  United  States  (le). 

Of  the  introduction  of  these  and  other  foreign 
plants  we  have  satisfactory  records  ;  but  there  are 
many  others  which  may  owe  their  presence  to  man's 
agency,  though  we  have  no  information  as  to  their 
arrival. 

It  has  long  been  recognised  that  several  members 
of  the  British    flora  are    related    to  Scandinavian 


22  LINKS   WITH  THE   PAST  [ch. 

species.  The  Scandinavian  flora,  as  Sir  Joseph 
Hooker  says  in  his  well-known  paper  on  the  'Out- 
lines of  the  Distribution  of  Arctic  plants,'  '  not  only 
girdles  the  globe  in  the  Arctic  Circle,  and  dominates 
over  all  others  in  the  North  Temperate  Zone  of  the 
Old  World,  but  intrudes  conspicuously  into  every 
other  temperate  flora,  whether  in  the  northern  or 
southern  hemisphere,  or  on  the  Alps  of  tropical 
countries '(17).  The  vicAV  generally  held  is  that  during 
the  Glacial  period  this  Arctic  flora  was  driven 
South,  and  aided  by  land-bridges,  which  were  after- 
wards submerged,  many  of  the  northern  migrants 
found  a  more  congenial  home  in  Britain.  It  is  how- 
ever by  no  means  improbable  that  this  conclusion 
may  have  to  be  considerably  modified.  Mr  and  Mrs 
Reid,  as  the  result  of  their  careful  analysis  of  the 
Pre-Glacial  Flora  of  Britain,  express  the  opinion  that 
Hhe  pre-glacial  plants  suggest  climatic  conditions 
almost  identical  with  those  now  existing,  though 
slightly  warmer'  (27,  2).  It  is  noteworthy  that  the 
list  of  plants  given  in  their  paper  does  not  include 
any  typical  Arctic  species.  The  occurrence  on  the 
mountains  of  Scotland  and  elsewhere  of  such  plants  as 
Silene  acaulis,  Dry  as  octopetaJa,  Saxlfraga  oppositi- 
folia  and  other  Saxifrages,  Ruhns  chamaemorus  (the 
Cloudberry),  and  the  dwarf  Birch  illustrate  the  Arctic- 
Alpine  element  in  our  flora. 

The  opinion  is  held  by  many  Swiss  botanists  that 


II]  GEOGRAPHICAL  DISTRIBUTION  23 

their  Alpine  species  have  in  large  measure  been 
derived  from  non-glaciated  parts  of  the  Pyrenees,  that 
is  from  a  region  which  was  presumably  able  to  retain 
its  flora  at  a  time  Avhen  more  northern  lands  were 
exposed  to  extreme  Arctic  conditions.  My  friend 
Dr  Moss  believes  that  some  of  the  so-called  Scandi- 
navian plants  came  to  Britain  from  Central  Europe 
after  the  retreat  of  the  ice  ;  if  this  view  is  correct  it 
means  that  some  at  least  of  our  iVrctic-Alpine  plants 
reached  these  islands  by  a  southern  rather  than  by 
a  northern  route. 

Interesting  examples  of  far-travelled  northern 
plants  recently  described  by  Professor  Engler  of 
Berlin  afford  additional  illustrations  of  the  general 
principles  enunciated  many  years  ago  by  Sir  Joseph 
Hooker.  A  species  of  flowering  Rush,  Luzula 
spicata  var.  simensis,  occurs  at  an  altitude  of  3600 
metres  in  Abyssinia  and  on  Kilimanjaro.  Luzula 
spicata  is  found  in  the  whole  of  the  Arctic  and 
Subarctic  belt  in  Scotland,  Auvergne,  the  Jura 
mountains,  and  elsewhere.  The  species  probably 
began  its  career  in  the  northern  hemisphere  where 
it  grew  abundantly  on  the  higher  ground  in  the 
Arctic  Circle :  it  eventually  travelled  along  the 
North  American  Andes  and  appeared  in  Mexico 
under  a  guise  sufficiently  distinct  to  warrant  the 
use  of  another  name,  Luzula  racemosa.  In  an 
eastern  direction  it  reached  the  Himalayas  and  is 


24  LINKS   WITH  THE   PAST  [cu. 

]oi)i'osentc(l  in  Abyssinia  by  a  closely  allied  form. 
P^roni  Abyssinia  to  Kilimanjaro  Luzula  spicata  '  had 
to  travel  a  long  distance  ;  but  it  is  not  impossible 
that  it  either  still  exists  or  has  existed  previously 
on  a  few  of  the  high  mountains  between  Abyssinia 
and  Kenia,  from  which,  having  advanced  to  the 
Kilimanjaro,  it  again  produced  new  forms.... At  any 
rate,  it  is  impossible  to  do  without  distribution  of 
seeds  of  alpine  plants  by  air-currents  or  by  birds 
from  one  mountain  to  the  other  in  explaining  the 
history  of  distribution '(is). 

The  majority  of  British  plants  are  identical  with 
species  in  Central  and  Northern  Europe  :  of  these, 
some  are  among  the  most  Avidely  spread  English 
species,  e.g.  the  Daisy  and  Primrose,  while  others, 
such  as  the  Oxlip  {Prinvda  elathr),  are  confined  to 
the  Eastern  counties,  and  others,  such  as  the  Cheddar 
Pink  {Dlanthus  caesius),  are  restricted  to  Western 
counties. 

Before  considering  a  small  section  of  the  British 
flora  which  is  the  most  interesting  from  the  point  of 
view  of  origin,  a  short  digression  may  be  allowed  in 
order  to  call  attention  to  the  importance  of  a  branch 
of  science  which  Darwin  spoke  of  as  'that  grand 
subject,  that  almost  keystone  of  the  laws  of  creation, 
geographical  distribution,'  and  in  1847  referred  to 
as  '  that  noble  subject  of  which  we  as  yet  but  dimly 
see  the  full  bearing.'     It  was  largely  as  the  results 

PROPERTY  OF 

Ai&M.COLLEGFURRARY, 


II]  GEOGRAPHICAL  DISTRIBUTION  25 

of  his  study  of  distribution  in  the  Galapagos  Islands 
that  Darwin  determined  to  'collect  blindly  every 
sort  of  fact  which  bears  anyway  on  what  are  species.' 
The  acceptance  of  the  view^  'that  each  species  was 
first  produced  within  a  single  region '(19),  raises  the 
subject  of  geographical  distribution  to  a  far  higher 
plane  than  it  occupied  in  pre-Darwinian  days.  Al- 
though most  people  are  familiar  with  some  of  the 
commoner  means  by  which  plants  are  able  to  colonise 
new  ground  through  the  adaptation  of  their  fruits  and 
seeds  to  various  methods  of  transport,  the  conception 
of  a  plant  as  a  stationary  organism  tends  to  prevent 
due  allowance  being  made  for  the  comparative 
facility  with  which,  in  the  course  of  successive 
generations,  a  species  is  able  to  wander  from  place 
to  place.  The  individual  animal  is  endowed  with 
powers  of  locomotion  enabling  it  to  seek  new  feeding- 
grounds  and  to  avoid  enemies ;  but  with  the 
exception  of  some  of  the  simplest  forms  a  plant 
cannot  move — 'le  niatin  la  laisse  oii  la  trouve  le 
soir.'  ^ 

The  rate  of  travel  may  or  may  not  be  rapid,  but 
in  a  comparatively  short  time,  if  the  conditions  are 
favourable,  a  tree  may  spread  over  a  wide  area. 
Mr  Ridley,  Director  of  the  Botanic  Gardens,  Singa- 
pore, writes  as  follows  in  reference  to  the  rate  of 
travel  of  one  of  the  common  Malayan  trees  {Shorea 
leprosula),   which   bears   Avinged   fruits  particularly 


26  LINKS   WITH   THE   PAST  [ch. 

well  adapted  to  wind-transport :  '  If  we  assume  that  a 
tree  flowers  and  fruits  at  30  years  of  age  and  the  fruits 
are  disseminated  to  a  distance  of  100  yards,  that  the 
furthest  fruits  always  germinate  and  so  continue  in 
one  direction,  it  will  be  seen  that  under  such  most 
favourable  circumstances  the  species  can  only  spread 
800  yards  in  100  years,  and  would  take  58,0(50  years 
to  migrate  100  miles '(20). 

There  is,  however,  one  type  of  distribution — 
wliat  is  called  discontinuous  distribution — to  which 
special  attention  should  be  directed  on  account  of  its 
intimate  association  with  questions  relating  to  the 
past  history  of  living  organisms.  Many  examples 
might  be  quoted  from  both  the  animal  and  plant 
kingdoms  in  support  of  the  view  that  discontinuous 
distribution  is  a  criterion  of  antiquity.  When  identical 
or  very  nearly  identical  plants  occur  in  regions 
separated  from  one  another  by  areas  in  which  the 
particular  species  is  unknown,  the  inference  is  either 
that  the  surviving  individuals  are  remnants  of  a  large 
number  formerly  distributed  over  a  wider  continuous 
area,  or  that  in  the  course  of  evolution  similar  con- 
ditions in  widely  separated  areas  led  to  the  production 
of  identical  types.  The  former  view  is  much  the  more 
probable  :  it  is  consistent  with  the  conclusions  arrived 
at  on  other  grounds  as  to  the  connexion  betAveen 
discontinuous  distribution  and  ancient  lineage.  The 
explanations  of  the  widespread   occurrence  among 


II]         GEOGRAPHICAL  DISTRIBUTION         27 

different  races  of  similar  objects  or  legends  afford  an 
analogous  case.  As  Dr  Andrew  Lang  points  out  in 
Custom  and  Myth,  it  is  held  by  some  students  that 
the  use  of  the  bull  roarer — to  cite  a  specific  instance 
— by  different  peoples  denotes  descent  from  a  common 
stock,  though  he  considers  the  more  probable  ex- 
planation to  be  that  similar  minds,  working  with 
simple  means  towards  similar  ends,  might  evolve  the 
bull  roarer  and  its  mystic  uses  anywhere. 

The  Cedars  of  Lebanon  afford  an  interesting  ex- 
ample of  discontinuous  distribution.  They  illustrate 
how  a  species,  which  may  be  assumed  to  have 
originated  in  one  region,  in  the  course  of  its 
wanderings  may  undergo  slight  changes  until,  at 
a  later  stage  when  the  plants  have  disappeared  from 
parts  of  the  once-continuous  area,  the  remaining 
outlying  groups  of  individuals  are  spoken  of  under 
different  specific  names.  The  cedars  of  Lebanon, 
known  as  Cedrus  llbanl,  occur  as  isolated  groups 
on  the  Lebanon  hills  as  outliers  of  the  larger  forests 
of  the  Taunus  250  miles  distant.  The  African  cedar, 
Cedrus  atlantlca,  is  separated  from  the  Lebanon 
cedar  by  a  distance  of  1400  miles.  Approximately 
the  same  distance  divides  the  Lebanon  cedar  from 
the  deodar,  Cedrus  deodara,  which  extends  from 
Afghanistan  along  the  Himalayas  almost  to  the 
confines  of  Nepal.  Sir  Joseph  Hooker  regards  the 
three  cedars  as  varieties  of  one  species  which  once 


28  LINKS   WITH  THE   PAST  [ch. 

formed  a  continuous  forest :  he  attributes  the  present 
discontinuous  distribution,  in  part  at  least,  to  the 
effects  of  a  warmer  succeeding  a  colder  climate.  The 
less  favourable  conditions  drove  the  vegetation  of 
the  lowlands  to  seek  more  congenial  habitats  at 
higher  altitudes.  In  this  connexion  it  is  interesting 
to  find  that  in  Algeria  the  cedar  is  confined  to  the 
higher  ground  where  the  snow  lies  long  in  the 
spring(2i). 

The  Tulip  Tree  of  North  America  and  Central 
China  afibrds  one  of  many  examples  of  existing 
flowering  plants  which  illustrate  the  close  connexion 
between  present  distribution  and  past  history.  The 
genus  Liriodendron,  often  cultivated  in  the  south 
of  England,  is  now  represented  by  two  species,  the 
best  known  of  which — the  Tulip  Tree,  Liriodendron 
tidipera — extends  from  Vermont  to  Florida  and 
westwards  to  Lake  Michigan  and  Arkansas.  The 
leaves .  bear  a  superficial  resemblance  to  those  of 
the  Sycamore,  but  are  as  a  rule  easily  distinguished 
by  the  truncated  form  of  the  apex  ;  the  specific  name 
was  suggested  by  the  tulip-like  form  of  the  flowers. 
Fossil  leaves  of  Liriodendron  are  not  uncommon  in 
the  Cretaceous  rocks  of  Disco  Island  in  latitude  70°  N., 
where  they  occur  Avith  other  flowering  plants  which 
bear  striking  testimony  to  the  mildness  of  the  Cre- 
taceous climate  in  high  northern  latitudes.  One 
of  the  associated  flowering  plants  is  a  species  of 


II]         GEOGRAPHICAL   DISTRIBUTION  29 

Artocarpiis,  described  by  Dr  Nathorst  as  Artocarpus 
Dicksonl  which  bears  a  close  resemblance  to  ^1.  incisa 
the  bread-fruit  tree  of  the  southern  tropics  of  the 
Old  World.  Without  attempting  to  deal  fully  with 
the  past  history  of  Liriodendron,  it  may  be  confidently 
stated  that  the  records  of  the  rocks  are  consistent 
with  the  idea  of  antiquity  suggested  by  the  present 
distribution  of  the  two  surviving  species. 

Islands  such  as  Great  Britain  and  Ireland,  situated 
a  short  distance  from  a  continent,  contain  many  plants 
which  are  widely  spread  in  different  parts  of  the 
world,  together  with  a  very  small  number  peculiar 
to  the  British  Isles  though  closely  allied  to  species 
on  the  neighbouring ,  continent  or  to  plants  farther 
afield.  The  occasional  recognition  of  species  pre- 
viously believed  to  be  confined  to  Britain  tends  to 
reduce  the  short  list  of  our  endemic  types. 

An  enquiry  into  the  origin  of  an  island  flora 
involves  a  consideration  of  the  data  in  regard  to 
changes  in  level  and  relative  distribution  of  land 
and  water  in  the  course  of  geological  evolution.  It 
is  generally  agreed  that  at  no  distant  date,  in  a 
geological  sense.  Great  Britain  and  Ireland  were 
united  to  the  continent.  There  is,  however,  another 
fact  to  reckon  with,  namely  the  prevalence  of  Arctic 
conditions  in  northern  Europe  when  a  thick  sheet  of 
ice  spread  over  the  greater  part  of  the  British  Isles. 
There  can  be  no  doubt  that  the  severity  of  the  climate 


30  LINKS   WITH   THE   PAST  [CH. 

during  the  Glacial  period  was  such  as  to  destroy 
a  large  proportion  of  the  vegetation.  The  question 
is,  Avere  all  the  flowering  plants  destroyed  or  were 
some  of  the  hardier  species  able  to  survive,  either  on 
the  higher  peaks  which  kept  their  heads  above  the 
level  of  the  ice  or  on  the  southern  fringe  of  England 
beyond  the  ice-covered  region  ?  It  is  impossible  to 
give  a  definite  answer  :  the  probability  is  that  nearly 
all  the  pre- Glacial  species  were  destroyed,  but  it  is 
not  impossible  that  some  Alpine-Arctic  plants  escaped 
extinction,  while  others  retreated  to  more  southern 
and  less  Arctic  areas  by  means  of  a  land-connexion 
with  France  or  crossed  the  intervening  sea  by  ocean- 
currents,  by  animal  agency,  or  by  wind. 

Although  we  possess  but  imperfect  information  as 
to  the  extent  and  duration  of  land-bridges  between 
Britain  and  the  continent,  there  are  no  special 
difficulties  in  the  way  of  accounting  for  the  presence 
of  Scandinavian,  Germanic,  and  other  elements  in  the 
British  flora.  There  are,  however,  other  and  more 
difficult  problems  to  consider  in  reference  to  a  small 
group  of  flowering  plants  which  are  met  with  in  the 
west  and  south  of  Ireland,  also,  to  a  less  extent,  in 
Cornwall  and  in  a  few  other  localities  in  the  south- 
west of  England.  In  Connemara  in  the  west  of  Ireland, 
where  hard  frosts  are  unknown  and  winter  snows  are 
rare,  there  are  three  kinds  of  Heath,  St  Dabeoc's  Heath 
(Dabeocia  poli/olia),  the  Mediterranean  Heath  (Erica 


II]  GEOGRAPHICAL  DISTRIBUTION  31 

mediterrmiea)  and  Erica  Maclaii  Avhicli  are  not 
found  elsewhere  in  the  British  Isles  or  in  the  whole 
of  northern  Europe,  but  reappear  in  the  P3a'enees. 
The  London  Pride  (Saxlfraga  umhrosa),  another 
Pyrenean  plant,  grows  on  the  south  and  west  coast 
of  Ireland  from  Waterford  to  Donegal.  Arbutus 
Unedo,  the  Strawberr}^  tree,  which  flourishes  in  the 
Killarney  district  of  County  Kerry  and  occurs  in 
neighbouring  localities,  has  a  Avide  distribution  in 
the  Mediterranean  region.  Devonshire  and  Cornwall 
possess  two  other  Heaths,  Erica  ciliaris,  which  ex- 
tends into  Dorsetshire  and  occurs  in  north  Brittany, 
and  Erica  vagans,  both  Pyrenean  species,  while  a 
]\Iediterranean  plant.  Gladiolus  illyriciis,  grows  in  the 
New  Forest. 

In  1846  Edward  Forbes  dealt  with  the  problems 
presented  by  the  distribution  of  British  plants  in  an 
essay  which  has  exercised  a  far-reaching  influence. 
When  Forbes  published  his  work,  comparatively  little 
was  known  as  to  the  possibilities  of  transport  of  seeds 
and  fruits  across  barriers  of  water (22).  His  conviction 
that  the  known  means  of  dispersal  were  insufficient 
to  account  for  the  presence  of  Mediterranean  or 
Lusitanian  plants  in  Ireland  led  him  to  turn  to 
geology  for  a  solution  of  the  problem.  He  was  thus 
led  to  put  forward  the  view  that  in  the  course  of 
the  Tertiary  period  when,  as  we  know  from  palae- 
ontological  evidence,  the  climate  of  north  and  west 


3-2  LINKS  WITH   THE   PAST  [cH. 

Europe  was  iniich  warmer  than  it  is  now,  and  long- 
before  the  beginning  of  the  climatic  changes  which 
culminated  in  the  (Jlacial  period,  there  was  a  land- 
connexion   between   the   west   of    Ireland    and   the 
south-w^est    of   the    continent.     Mr   Praeger,   whose 
work  on  the  Irish  flora  is  well  known  to  systematic 
botanists,  agrees  with  the  conclusions  of  Forbes,  and 
sees  in  the   Portuguese   and  Mediterranean   plants 
'relics  of  a  vegetation  which  once  spread  along  a 
bygone  European  coast-line  which  stretched  unbroken 
from   Ireland  to   Spain '(23).     If  this   explanation   is 
correct  it  entitles  Arbutus,  St  Dabeoc's  heath  and 
other  members  of  this  southern  group  to  be  regarded 
as  a  very  old  section  of  our  flora.     There  is,  however, 
another  side  to  the  question  :  granting  that  a  certain 
number  of  Irish  plants  were  able  to  w^ithstand  the 
rigours  of  an  Ice  age,  it  is  hardly  likely  that  the 
strawberry  tree  and  other  southern  types,  which  it 
is   admitted  flourish   in   the   south-west   of  Ireland 
because  of  the  mildness  of  the  climate,  w^ere  of  the 
number  of  those  which  endured  an  extreme  Arctic 
phase.     Moreover,  if  these  Mediterranean  species  are 
survivals  from  the  Tertiary  period,  if  they  have  been 
isolated   since   pre-( glacial  days  as  an  outlier  of  a 
southern  flora,  Ave  might  fairly  expect  that  during 
the   long  interval   between    their    arrival    and    the 
present  day  ncAV  forms  would  have  been  produced 
closely  related   to,  though   not  identical   with,   the 


II]  GEOGRAPHICAL  DISTRIBUTION  33 

parent  types.  This,  however,  has  not  been  proved  to 
be  the  case.  Darwin  in  speaking  of  Forbes'  Essay  in 
a  letter  to  de  CandoUe  in  1863  says  that  he  differs 
from  most  of  his  contemporaries  'in  thinking  that 
the  vast  continental  extensions  of  Forbes,  Heer,  and 
others  are  not  only  advanced  without  sufficient  evi- 
dence, but  are  opposed  to  much  weighty  evidence'(i2). 
The  alternative  view  is  to  regard  Arbutus  and  its 
compatriots  as  post- Glacial  arrivals  and  not  as  sur- 
vivals from  a  widely  spread  Tertiary  flora. 

A  recently  published  account  of  the  New  Flora 
of  the  volcanic  island  of  Krakatau  furnishes  an 
instructive  and  remarkable  demonstration  of  the 
facility  with  which  a-  completely  sterilised  island, 
separated  by  several  miles  of  ocean  from  neigh- 
bouring lands,  may  be  restocked  with  vegetation  (24). 
In  1883  the  island  of  Krakatau,  then  densely  covered 
with  a  luxuriant  tropical  vegetation,  was  partially 
destroyed  by  a  series  of  exceptionally  violent  volcanic 
explosions.  After  this  catastrophe  only  a  third  of 
the  island  was  left :  the  surface  was  deeply  covered 
by  pumice  and  volcanic  ash  and  no  vestige  of  life 
remained.  In  1906  a  party  of  botanists  who  spent 
a  few  hours  on  Krakatau  collected  137  species  of 
plants  :  the  vegetation  was  in  places  so  dense  that 
it  was  with  the  greatest  difficulty  they  penetrated 
beyond  the  coastal  belt,  and  some  of  the  trees  had 
reached  a  height  of  50  feet.     The  seeds  and  fruits 

s.  3 


34  LINKS  WITH   THE   PAST  [ch.  ii 

of  this  new  flora  have  been  carried  by  ocean-currents, 
by  wind,  and  by  the  agency  of  birds  from  other 
islands  in  the  ^lalay  Archipelago.  The  nearest 
islands,  except  the  small  island  of  Sebesi,  about 
12  miles  distant,  are  Java  and  Sumatra,  separated 
from  Krakatau  by  a  stretch  of  water  about  25  miles 
in  breadth.  It  is  reasonable  to  wonder  whether,  had 
Forbes  known  of  this  and  similar  modern  instances 
of  the  capabilities  of  plants  as  travellers,  he  would 
have  adopted  the  view  he  did.  In  this  connexion  it 
may  be  added  that  in  recent  years  the  glaciation  of 
Ireland  has  been  shown  to  be  more  extensive  than  it 
was  believed  to  be  when  Forbes  wrote  his  essay. 

There  would  seem  to  be  no  insuperable  objection 
to  the  conclusion  that  the  Mediterranean  plants  in 
Ireland  and  in  the  south  of  England  reached  their 
present  home  after  the  retreat  of  the  ice  at  the 
end  of  the  Glacial  period,  and  after  Ireland  became 
an  island.  A  full  consideration  of  the  problem  is 
beyond  the  scope  of  this  book,  but  I  have  briefly 
stated  the  case,  not  with  the  authority  of  an  expert 
but  in  order  to  draw  attention  to  a  particularly 
fascinating  study  in  plant-migration. 

In  a  volume  by  W.  Canton  entitled  A  ChikVs 
book  of  Saints  a  story  is  told  in  which  the  presence 
in  Ireland  of  Mediterranean  species  receives  a  more 
picturesque  explanation.  The  Monk  Bresal  was  sent 
to  teacli  the  brethren  in  a  Spanish  monastery  the 


Fig.  2,     Eriocanlon  septangulare  With,     West  Conneniara. 
(Photograph  by  Mr  W.  R.  Welch.) 


3—2 


36  LINKS   WITH   THE   PAST  [CH. 

music  of  Irish  choirs.  In  later  years  Bresal  longed 
for  a  sight  of  his  native  land,  though  he  loved  his 
home  and  '  every  rock,  tree,  and  flower "  in  his  adopted 
country.  After  returning  to  Ireland,  his  thoughts 
reverted  to  Spain  ;  '  it  appeared  to  him  as  though 
he  was  once  again  in  a  granite  nook  among  the  rocks 
beside  the  Priory ' ;  he  saw  the  ice-plant  with  its 
little  stars  of  white  flowers  sprinkled  with  red  (the 
London  Pride)  and  a  small  evergreen  tree  from  which 
he  had  often  gathered  the  orange-scarlet  berries 
(Arbutus).  The  Prior  of  the  Spanish  monastery  '  with 
heavenly  vision  saw  Bresal  gazing  at  the  evergreen 
tree  and  the  ice-plaut,  and  turning  to  the  trees 
blessed  them  and  commended  them  to  go  and  make 
real  his  dream.  As  Bresal  brushed  away  his  tears 
he  saw  with  amazement  at  his  feet  the  ice-plant  and 
hard  by  the  evergreen  tree.' 

The  plant  represented  in  Fig.  2  is  another 
British  species  which  tasks  the  ingenuity  of  students 
of  plant-geography.  This  is  the  Pipe  Wort  {Erio- 
canlon  sejjtaugulare),  the  sole  representative  in 
Europe  of  a  certain  family  of  Monocotyledons  :  it 
flourishes  in  the  west  of  Ireland  and  in  the  western 
islands  of  Scotland  but  nowhere  else  in  Europe  ;  it  is 
native  on  the  other  side  of  the  Atlantic  in  Canada 
and  the  northern  United  States  of  America.  Mr 
Praeger  in  describing  the  striking  mixture  of  species 
in  the  west  of  Ireland  writes,  '  The  pool  from  which 


II]  GEOGRAPHICAL  DISTRIBUTION         37 

we  gather  the  American  Pipe  Wort  is  fringed  with 
Pyrenean  Heathers.  The  cracks  which  are  filled  with 
the  delicate  green  foam  of  the  maiden  hair  are  set  in 
Bearberry  and  Spring  Gentian  ;  Hahenaria  intacta, 
far  from  its  Mediterranean  home,  sends  up  its  flower- 
spikes  through  carpets  of  mountain  Avens ;  and 
St  Dabeoc's  Heath  and  the  dwarf  Juniper  straggle 
together  over  the  rocky  knolls '(25). 

The  presence  of  Eriocaulon  on  the  western  edge 
of  Europe  may  be  attributed  to  migration  in  pre- 
Glacial  days  from  North  America  by  way  of  a  land- 
connexion,  of  which  Greenland  and  Iceland  represent 
surviving  portions.  The  opinion  held  by  Forbes,  and 
advocated  by  some  later  naturalists,  that  the  southern 
companions  of  Eriocaulon  in  the  west  of  Ireland  are 
survivors  from  a  Tertiary  flora  which  have  lived 
through  the  Ice  Age,  is  consistently  extended  to  the 
Pipe  Wort.  On  the  other  hand,  before  yielding  to 
the  temptation  to  regard  these  American  and  Medi- 
terranean species  as  links  with  the  Tertiary  period, 
we  must  be  convinced  that  the  possibilities  of 
post-Glacial  introduction,  even  without  the  aid  of 
land-bridges,  have  been  exhausted.  The  Pipe  Wort 
is  a  botanical  puzzle  which  affords  a  good  example  of 
the  accession  of  interest  to  field-botany  effected  by  a 
knowledge  of  the  distribution  of  the  component 
members  of  the  British  flora.  The  problem  of  its 
past  history  suggests  an  experimental  enquiry  into 


38  LINKS   WITH   THE   PAST  [ch.  ii 

the  adaptability  of  its  seeds  to  dispersal,  and  em- 
phasises the  importance  of  the  co-operation  of 
botanists  and  geologists  in  a  common  endeavour  to 
trace  the  origin  of  British  plants. 

In  addition  to  the  Pipe  Wort,  mention  may  be 
made  of  three  other  American  flowering  plants 
recognised  in  the  Irish  flora.  Sisi/rinchiimi  angusti- 
folium  recorded  from  the  west  of  Ireland  is  native 
in  temperate  North  America  ;  the  orchid,  Spiranthes 
romanzoffiana,  met  with  in  the  south  and  north  of 
Ireland,  is  widely  spread  in  Canada  and  the  northern 
States,  while  Sisyrinchium  californiciiin,  a  native 
of  California  and  Oregon,  was  discovered  by  Mr  Mar- 
shall in  marshy  meadow-land  near  Wexford  (26).  In 
the  case  of  the  more  recently  discovered  American 
immigrants,  the  possibility  of  human  introduction 
must  be  borne  in  mind,  though  there  are  no  special 
reasons  for  doubting  that  some,  as  in  the  case  of  Erio- 
caulon,  reached  the  Irish  coast  by  natural  agencies. 


CHAPTER  III 

THE  GEOLOGICAL  RECORD 

'  All  the  Epochs  of  the  Past  are  only  a  few  of  the  front  carriages, 
and  probably  the  least  wonderful,  in  the  van  of  an  interminable 
procession.'     J.  B.  Bury  {The  Science  of  History). 

The  portion  of  the  earth's  surface  accessible  to 
investigation  is  made  up  in  part  of  accumulations 
of  old  sediments,  some  indistinguishable  from  the 
shingle,  sand,  and  mud  now  in  process  of  formation 
by  the  ceaseless  action  of  denudation  ;  others  have 
been  hardened,  gently  folded  or  violently  contorted 
and  so  far  altered  by  crust-movements  as  to  render 
their  sedimentary  origin  well  nigh  unrecognisable. 
It  is  these  sediments  of  former  ages,  the  dust  of  lost 
continents,  in  which  are  preserved  the  majority  of 
the  fragmentary  remains  of  plants  and  animals,  the 
flotsam  and  jetsam  of  successive  phases  of  evolution. 

The  crust  of  the  earth,  as  Darwin  wrote,  '  with  its 
imbedded  remains  must  not  be  looked  at  as  a  well 
filled  museum,  but  as  a  poor  collection  made  at 
hazard   and   at  rare  intervals '(19).     It   is   from   this 


40  LINKS  WITH  THE  PAST  [ch. 

imperfect  record  that  we  seek  to  discover  the  relative 
antiquity  of  the  several  groups  or  genera  of  living 
plants,  and  in  the  structure  of  extinct  types  we 
endeavour  to  discover  connecting  links  between 
divisions  of  the  plant  kingdom  which  in  the  course 
of  evolution  have  retained  little  or  no  signs  of  a 
common  descent. 

Sir  Joseph  Hooker  in  a  letter  to  Darwin  in  1859 
speaks  of  his  'conviction  that  we  have  not  in  a 
fossilised  condition  a  fraction  of  the  plants  that  have 
existed,  and  that  not  a  fraction  of  those  we  have  are 
recognisable  specifically '(12).  Considering  the  nature 
of  the  palaeontological  documents  the  wonder  is  how 
much  they  have  taught  us,  and  we  may  look  with 
confidence  to  the  results  of  future  research  in  a  field 
of  which  tlie  importance  has  only  recently  been 
appreciated.  With  the  strata  of  sedimentary  origin 
are  frequently  associated  igneous  rocks,  and  in  many 
continental  regions,  as  in  the  majority  of  oceanic 
islands,  the  crust  of  the  earth  consists  wholly  of 
volcanic  material  or  of  rocks  produced  by  the  gradual 
solidification  of  molten  magmas.  Rocks  composed 
mainly  of  carbonate  of  lime,  such  as  limestones  and 
chalk,  bear  witness  to  ocean  beds  or  to  sediments 
deposited  on  the  floors  of  inland  seas  beyond  the 
reach  of  land  detritus  where  coral  reefs  were  reared 
or  the  shells  and  other  calcareous  skeletons  of 
animals  supplied  the  material  for  future  land.     In 


Ill]  THE   GEOLOGICAL  RECORD  41 

such  rocks  the  remains  of  calcareous  seaweeds  are 
frequently  recognisable  and  occasionally,  as  in  the 
English  chalk,  fragments  of  wood  testify  to  transport 
from  a  distant  land. 

While  there  is  little  difficulty  in  explaining  the 
nature  of  much  of  the  earth's  crust,  in  several  parts  of 
the  world  the  strata  are  totally  unfossiliferous  and 
closely  simulate  crystalline  rocks.  In  many  cases 
it  is  believed  that  such  strata  represent  ancient 
sediments  which  in  the  course  of  ages  have  been 
reduced  by  metamorphic  agencies  to  a  condition 
which  has  obscured  or  entirely  obliterated  all  traces 
of  their  pristine  state. 

Since  the  pioneer  work  of  William  Smith,  who 
in  the  early  days  of  the  nineteenth  century  first 
realised  the  importance  of  fossils  as  aids  to  the 
determination  of  relative  age,  geologists  have  devoted 
themselves  to  the  task  of  correlating  the  sedimentary 
rocks  of  the  world,  using  as  criteria  the  order  of 
superposition  of  the  strata  and  the  nature  of  their 
organic  remains.  The  result  has  been  to  classify 
portions  of  the  earth's  crust  into  periods  or  chapters, 
which  together  constitute  a  record  of  geological 
evolution  as  complete  as  it  is  possible  to  obtain  from 
the  available  data.  The  accompanying  table  shows 
the  order  of  sequence  of  the  epochs,  which  stand  for 
terms  of  years  of  a  magnitude  beyond  our  powers  to 
grasp. 


42 


LINKS  WITH  THE  PAST 


[CH. 


The  division  of  geological  history  into  larger  and 
smaller  periods  does  not  imply  the  recui-rence  of 
sudden  revolutions  ;  it  is  in  some  measure  dictated 
by  considerations  of  convenience,  but  more  parti- 
cularly by  our  ignorance  of  certain  stages  in  the 
history  of  the  world  due  to  the  imperfection  of  the 
record. 


o^ 

'  Recent 

o 
o 

Pleistocene 

PUocene 

C5 

Miocene 

< 

g 

Oligocene 

,  Eocene 

f 

o 

Cretaceous 

1 

1 

Jurassic 

< 

o 
o 

Triassic 

GEOLOGICAL   TABLE. 

Showing  the  position  in  the  Geological  Series  of  the  strata  referred 
to  in  this  volume. 


Superficial  accumulations  containing  human 
remains  (Metal  age,  Neolithic  and  Palaeo- 
lithic ages,  Glacial  deposits) 

Cromer  Forest-bed,  etc. 

Absent  from  Britain. 

Bovey  Tracey  beds,  etc. 

London  Clay,  etc. 


( Chalk 

I  Wealden  beds 

(  Purbeck  and  Portland  beds  (Upper  Jurassic) 
\  Oolites  (Middle  Jurassic) 
[  Lias  (Lower  Jurassic) 

(Rhaetic  beds 
Reuper      ,,     (Marls  with  rock-salt,  etc.) 
Bunter      „ 


Ill]  THE  GEOLOGICAL  RECORD  43 

GEOLOGICAL  TABLE  (continued). 

''  _        .  (  Red  Sandstones,  etc. 

Permian  -; 

i  Magnesian  limestone 

Coal  Measures 

Carboniferous  -|  Millstone  Grit 

Carboniferous  limestone 

Devonian  limestones,  etc. 


Devonian 

Old  Eed  Sandstones 


{ 

Slates,  sandstones, 


_.,     .  f  Sandstones,  shales, 

Silurian  ^  '  ' 

some  limestone 


Ordovician       ,  ^^  ,  , 

[  Volcanic  rocks,  etc. 

Cambrian  Slates,  Sandstones,  etc. 

[  Slates,  Volcanic  rocks,  etc. 
V  or  Archaean    j 

In  certain  parts  of  the  world,  as  for  example  the 
north-west  Highlands  of  Scotland,  the  Malvern  Hills, 
Scandinavia,  and  in  many  other  regions  in  Europe 
and  North  America,  geologists  have  recognised  what 
they  believe  to  be  the  foundation  stones  of  the 
world.  These  Archaean  rocks,  which  underlie  the 
oldest  fossiliferous  strata,  belong  to  a  period  of 
geological  evolution  from  which  it  appears  to  be 
hopeless  to  obtain  any  light  as  to  the  nature  of  the 
contemporary  organic  world.  The  earliest  vestiges  of 
life  so  far  discovered  exhibit  a  high  degree  of  organisa- 
tion, which  unmistakably  points  to  their  being  links  in 
a  chain  extending  far  beyond  the  limits  of  the  oldest 


44  LINKS  WITH  THE   PAST  [cii. 

Cambrian  strata  in  which  recognisable  fossils  first 
occur.  The  rocks  of  the  Cambrian  and  Ordovician 
epochs,  as  represented  by  the  grits,  shales,  slates 
and  other  sedimentary  strata  in  Wales,  Shropshire,  the 
Lake  district  and  elsewhere,  though  in  places  rich  in 
the  remains  of  animals,  aftbrd  no  information  in  regard 
to  the  land  vegetation.  From  the  succeeding  Silurian 
epoch  very  little  evidence  has  been  gleaned  as  to  the 
nature  of  the  flora,  and  it  is  not  until  we  come  to  the 
sedimentary  rocks  of  the  Devonian  era  that  records 
of  plant-life  occur  in  any  abundance.  The  almost 
complete  lack  of  botanical  data  in  the  pre-Devonian 
formations  is  in  part  due  to  the  fact  that  these  older 
rocks  consist  to  a  large  extent  of  marine  deposits 
formed  under  conditions  unfavourable  to  the  preser- 
vation of  plants.  That  the  land-surfaces  of  the  older 
Palaeozoic  eras  supported  an  abundant  vegetation 
there  can  be  little  doubt.  The  relics  of  plant-life 
furnished  by  the  Devonian  and  succeeding  formations 
represent  the  upper  branching-systems  of  a  deeply 
rooted  and  spreading  tree,  the  lowest  portions  of 
which  have  been  destroyed  or  have  left  no  sign  of 
their  existence. 

In  descending  the  Geological  series,  we  begin  with 
superficial  deposits,  such  as  peat  and  river-gravels 
found  subsequently  to  the  underlying  boulder-clay  of 
the  Glacial  period.  The  remains  of  forest  trees  pre- 
served in  the  peat  and  in  submerged  forests  round 


Ill]  THE   GEOLOGICAL  RECORD  45 

the  coast  connect  the  vegetation  of  the  historic  period 
with  that  of  the  Neolithic  age.  At  the  base  of  the 
Pleistocene  series,  the  name  given  to  the  latest 
chapter  of  geological  history,  we  find  evidence  of  the 
prevalence  of  arctic  conditions  in  the  Avidely  spread 
boulder-clays  and  other  deposits  of  the  Glacial  period. 

From  deposits  of  post-Glacial  date  abundant  plant 
remains  have  been  obtained,  but  we  cannot  say  with 
any  degree  of  certainty  what  proportion  of  these 
plants  remained  in  Britain  during  the  Ice  age,  and 
whether  the  greater  jiart  of  the  vegetation,  the  relics 
of  which  have  been  discovered  in  pre-Glacial  beds, 
was  destroyed  or  driven  south  by  the  advancing  ice. 
We  may  briefly  consider  some  of  the  more  interesting 
facts  brought  to  light  by  the  investigation  of  the 
fossil  plants  in  the  Lower  Pleistocene  and  Upper 
Tertiary  beds.  It  is  mainly  to  the  researches  of 
Mr  Clement  Reid  into  the  vegetation  of  Britain 
immediately  preceding  the  Glacial  period,  that  our 
knowledge  of  this  phase  of  the  history  of  the  British 
flora  is  due. 

On  the  coast  of  Norfolk  in  the  neighbourhood  of 
Cromer  the  sections  of  the  cliffs  reveal  the  existence 
of  a  succession  of  sands,  clays,  and  gravels  underlying 
Glacial  deposits ;  this  material  was  probably  laid 
down  near  the  mouth  of  the  ancient  Rhine,  which  in 
the  latter  part  of  the  Tertiary  period  flowed  across 
a  low  area,  which  is  now  occupied  by  the  shallow 


46 


LINKS  WITH  THE  PAST 


[CH. 


southern    half    of    tlie    North    Sea(27).     The    plant- 
fragiiients  found  in  these  river-sediments  indicate  a 


^ 


9*.r  >  ■ 


«<5^ 


i^ff^ 


Fig.  3.  Pre-Glacial  plants  from  Mundesley  (A),  Norfolk  and  Pakefield 
(B,  C),  Suffolk.  (Photographs  by  Mr  Clement  Keid  and  Mrs 
E.  M.  Raid.)  A.  Bidens  tripartita  Linn.  (  x  6)  ;  B.  Picea  excelsa 
Linn.  (nat.  size).     C.     Stellaria  holostea  Linn.  ( x  12). 


Ill] 


THE   GEOLOGICAL   RECORD 


47 


temperate  climate.  Among  the  plants  of  this  pre- 
Glacial  flora  are  many  familiar  British  species,  such  as 
Caltha  2)alustris  (marsh  marigold),  species  of  butter- 
cup, Stellaria  holostea  (greater  stichwort)  (Fig.  3,  C), 
Bidens  tripartita  (bur-marigold)  (Fig.  3,  A),  maple, 


Fig.  4.     Trapa  natans  Linn.  (nat.  size).     From  Mundesley. 
(Photographs  by  Mr  and  Mrs  Keid.) 


hawthorn,  the  alder,  hazel,  the  yew,  Scots  pine  and 
numerous  others.  If,  as  is  not  improbable,  these 
pre-Glacial  plants  were  swept  away  by  the  subsequent 
arctic  conditions,  the  great  majority  of  them  returned 
to  their  old  home  when  a  warmer  climate  ensued. 


48  LINKS   WITH   THE   PAST  [ch. 

There  are  however  some  pre-Glacial  plants,  such  as 
the  spruce  fir  (Picea  excelsa),  a  cone  of  which  is 
shown  in  Fig.  3,  B,  the  water  chestnut,  Trapa  natans 
(Fig.  4),  and  a  few  other  species  no  longer  repre- 
sented in  the  British  flora.  The  genus  Trapa  is 
a  striking  exanii)le  of  a  flowering  plant  which  has 
disappeared  since  the  Tertiary  period  from  many 
parts  of  Europe,  including  England,  most  of  Sweden, 
and  from  several  regions  in  northern  Europe.  It  still 
grows  in  a  few  localities  in  Switzerland  and  in  some 
of  the  Italian  lakes.  In  pre-Glacial  times  the  water 
chestnut  was  widely  spread  from  Portugal  and  England 
in  the  west  to  Siberia  in  the  east,  and  its  hard  four- 
pronged  nuts  have  been  recorded  from  many  post- 
Glacial  peat-moors  in  the  north  of  Europe. 

From  the  so-called  Cromer  forest-bed  and  as- 
sociated deposits  on  the  Norfolk  coast  several 
pre-Glacial  plants  have  been  obtained,  indicating 
a  temperate  climate  during  this  phase  of  the 
Pleistocene  period.  A  few  arctic  species,  such  as 
the  dwarf  birch  and  arctic  willow  obtained  from  the 
deposits  next  above  the  Cromer  forest-bed,  herald 
the  near  approach  of  glacial  conditions. 

It  may  be  remarked  in  passing  that  no  satisfactory 
evidence  has  been  discovered  in  Britain  of  the 
existence  of  man  in  this  part  of  Europe  in  pre-Gla- 
cial days  :  it  is,  however,  believed  that  flints  from 
Tertiary  strata  on  the  continent  show  traces  of  human 


Ill]  THE   GEOLOGICAL   RECORD  49 

workmanship.  As  Sir  Edwin  Ray  Lankester  said  in 
1905,  'It  is  not  improbable  that  it  was  in  the  remote 
period  known  as  the  Lower  Miocene — remote  as  com- 
pared with  the  gravels  in  which  Eoliths  [primitive 
stone  implements]  occur — that  Natural  Selection 
began  to  favour  that  increase  in  the  size  of  the  brain 
of  a  large  and  not  very  powerful  semi-erect  ape  '(28). 

Though  comparatively  recent  in  terms  of  geological 
chronology,  the  remoteness,  according  to  ordinary 
conceptions  of  time,  of  the  Tertiary  period  is  brought 
home  to  us  when  we  endeavour  to  grasp  the  fact 
that  it  was  during  this  chapter  in  the  earth's  history 
that  some  of  our  highest  mountaiji-ranges,  such  as 
the  Alps,  the  Carpathians,  and  Himalayas  were  formed 
by  the  uplifting  of  piles  of  marine  sediments.  From 
Tertiary  strata  in  the  Isle  of  Wight,  on  the  Hamp- 
shire coast,  and  in  the  London  basin  numerous  fossil 
plants  have  been  obtained,  which  afford  convincing 
evidence  of  climatic  conditions  much  more  genial 
than  those  of  the  present  day.  The  presence  of  palm 
leaves  and  of  a  wealth  of  other  sub-tropical  plants 
in  Lower  Tertiary  beds  in  England  reveals  the 
existence  of  a  flora  differing  considerably  both  from 
that  in  the  uppermost  Tertiary  beds  of  Norfolk  and 
from  the  modern  British  flora,  but  closely  allied  to 
the  present  Mediterranean  flora. 

The  basaltic  columns  of  the  Giants'  Causeway  and 
of  the  Staffa  Cave,  and  the  terraced  rocks  which  form 

s.  4 


50  LINKS  WITH  THE  PAST         [ch.  iii 

so  characteristic  a  feature  in  the  contours  of  the 
Inner  Hebrides,  arc  portions  of  lava-floAvs,  which  in 
the  early  days  of  the  Tertiary  period  were  poured 
out  over  a  wide  area  of  land  stretching  from  the 
north-east  of  Ireland,  through  the  Western  isles  of 
Scotland,  the  Faroe  islands,  to  Iceland  and  Greenland. 
While  in  this  northern  region  volcanic  activity  was 
being  manifested  on  a  stupendous  scale,  a  shallow 
sea  extended  over  part  of  what  is  now  the  south- 
east of  England  in  which  was  deposited  a  considerable 
thickness  of  sedimentary  material  derived  from  the 
neighbouring  land.  In  this  upraised  sea-floor,  known 
as  the  London  cl^y,  which  is  exposed  in  the  Isle  of 
Sheppey  and  in  many  other  localities,  numerous  fossil 
fruits  and  fragments  of  wood  occur  in  association 
with  marine  shells.  The  fact  that  many  of  the  fruits 
were  ripe  at  the  time  of  their  entombment  led  some 
eighteenth  century  writers  to  assign  an  autumn  date 
to  the  universal  deluge.  One  of  the  Sheppey  fruits 
may  be  mentioned  as  an  especially  interesting  sample 
of  the  early  Tertiary  flora,  namely  the  genus  Nipa- 
dites,  so  named  from  the  very  close  resemblance  of 
the  fossils  to  the  fruits  of  the  existing  tropical  plant 
Nipa.  Nipa  frutlcaus,  sometimes  described  as  a 
stemless  palm  because  of  the  absence  of  the  erect 
stem  which  is  usually  a  characteristic  feature  of 
palms,  grows  in  brackish  estuaries  of  many  tropical 
countries  (Fig.  5,  A) :  it  has  long  leaves  not  unlike 


52  LINKS  WITH  THE  PAST  [CH. 

those  of  the  date-palm  and  bears  chisters  of  fruits 
as  large  as  a  man's  head  ;  a  single  fruit  is  two  or 
three  inches  long  and  its  hard  fibrous  shell  is  charac- 
terised b}^  four  or  five  longitudinal  ribs  (Fig.  5,  B). 
The  fruits  of  Nipa,  Avhich  may  be  carried  a  consider- 
able distance  by  ocean-currents  without  losing  the 
power  of  germination,  are  constantly  found  with  other 
vegetable  drift  on  the  beaches  of  tropical  islands.  The 
discovery  of  fruits  of  Nipa  (or  Nipadites),  hardly 
distinguishable  from  those  of  the  existing  species, 
in  Tertiary  beds  in  England,  Belgium,  in  the  Paris 
basin,  and  in  Egypt  afibrds  a  striking  instance  of 
changes  in  the  gQpgraphical  distribution  of  an  ancient 
plant  now  restricted  to  warmer  regions. 

While  the  higher  members  of  the  Cretaceous 
sj^stem,  as  seen  in  the  chalk  clifis  and  downs,  re- 
present the  upraised  calcareous  accumulations  on 
the  floor  of  a  fairly  deep  and  clear  sea,  the  lower 
members  testify  to  shallower  water  within  reach  of 
river-borne  sand  and  mud.  'During  the  Chalk 
period,'  as  Huxley  wrote,  'not  one  of  the  present 
great  physical  featui'es  of  the  globe  was  in  existence. 
Our  great  mountain  ranges,  Pyrenees,  Alps,  Hima- 
layas, Andes,  have  all  been  upheaved  since  the 
chalk  was  deposited,  and  the  Cretaceous  sea  flowed 
over  the  sites  of  Sinai  and  Ararat '  (29). 

The  Wealden  strata,  at  the  base  of  the  Cretaceous 
system,  as  seen  on  the  Sussex  coast,  in  parts  of  the 


Ill]  THE  GEOLOGICAL  RECORD  53 

Isle  of  Wight,  in  the  Weald  district  of  Kent  and 
neighbouring  counties,  point  to  the  existence  of  a 
lake  over  a  portion  of  the  south  of  England  and  of 
the  English  Channel.  The  remains  of  a  rich  Wealden 
flora  have  been  collected  from  these  Wealden  sedi- 
ments, notably  from  the  plant-beds  of  Ecclesbourne 
near  Hastings,  in  which,  so  far  as  we  know,  flowering 
plants  played  no  part  or  at  most  occupied  a  very 
subordinate  position.  A  few  fossil  leaves  have  been 
described  from  rocks  assigned  to  a  Wealden  age, 
— and  from  the  older  Stonesfield  Slate,  of  Jurassic 
age,  a  single  leaf  is  recorded, — which  seem  to  be 
those  of  Dicotyledons  ;  but  it  is  certain  that  even  in 
the  early  days  of  the  Cretaceous  period  the  present 
dominant  group  in  the  plant  kingdom  was  in  its 
infancy  and  in  many  regions  probably  unrepresented. 
When  we  glance  at  the  geological  table  and  consider 
that  in  all  the  floras  from  the  Wealden  down  to  the 
Devonian  period,  flowering  plants  played  no  part, 
we  are  able  to  appreciate  the  fact  of  their  rapid 
development,  referred  to  in  a  previous  chapter,  when 
once  this  highest  type  had  become  established. 

The  rocks  comprised  in  the  Jurassic  system  extend 
from  East  Yorkshire  to  the  coast  of  Dorsetshire ;  they 
consist  of  a  succession  of  limestones,  clays,  sandstones, 
and  a  few  thin  beds  of  impure  coal.  Sediments  of 
this  age  also  occur,  though  to  a  much  less  extent, 
on  the  north-east  coast  of  Scotland  and  in  a  few 


54  LINKS  WITH   THE   PAST  [ch. 

places  in  the  Inner  Hebrides.  Many  of  the  Jurassic 
strata  contain  only  marine  shells,  and  corals  are 
occasionally  abundant,  though  in  the  lower  members 
of  the  system  in  the  cliflfs  near  Lyme  Regis  and  at 
Whitby  fossil  plants  are  ftiirly  common.  It  is,  how- 
ever, from  the  middle  Jurassic  beds,  in  the  cliffs 
between  Whitby  and  Scarborough,  and  in  some 
inland  quarries  in  East  Yorkshire,  that  we  have 
obtained  the  richest  Jurassic  flora.  Rivers  from  a 
northern  land  laden  with  sediment  and  carrying  drift- 
wood, leaves  and  other  plant  fragments,  deposited 
their  burden  in  an  estuary  which  occupied  the  eastern 
edge  of  Yorkshire.  Sedimentary  rocks  laid  down 
towards  the  close  of  the  Jurassic  period  in  the  island 
of  Portland  in  the  south  and  on  the  Sutherland  coast 
in  the  north  have  furnished  valuable  records  of 
plant-life. 

The  passage  from  the  Jurassic  to  the  underlying 
Triassic  system  is  formed  by  some  shales  and  lime- 
stones in  South  Wales  containing  remains  of  fish  and 
other  marine  organisms.  These  so-called  Rhaetic 
beds  are  poorly  represented  in  the  British  area,  but 
on  the  continent  of  Europe  and  in  other  regions  the 
sediments  of  this  age  bulk  much  more  largely  and 
have  yielded  a  rich  collection  of  plants.  The  rocks 
of  the  upper  division  of  the  Triassic  system,  as  seen 
in  the  Midlands,  point  to  the  prevalence  of  desert 
conditions ;  and  in  the  grooved  sand-polished  surfaces 


Ill]  THE   GEOLOGICAL  RECORD  55 

of  granite  in  Charnwood  forest  we  have  a  glimpse  of 
a  Triassic  landscape.  The  salt-bearing  strata  of  this 
period  in  Cheshire  and  Worcestershire  suggest  con- 
ditions paralleled  at  the  present  day  in  the  Caspian 
and  Dead-Sea  regions.  The  vegetation  of  Britain,  and 
indeed  of  the  Avorld  as  a  whole,  seems  to  have  under- 
gone but  little  change  during  the  enormous  lapse  of 
time  represented  by  the  sediments  comprised  between 
the  Wealden  and  Triassic  periods.  The  Lower  Triassic 
flora  affords  evidence  of  a  change  in  the  facies  of  the 
vegetation  and  prepares  us  for  the  still  greater  dif- 
ferences revealed  by  a  study  of  the  Permian  and 
Carboniferous  floras.  To  the  student  of  evolution 
these  Palaeozoic  floras  are  of  special  interest  on 
account  of  the  facts  they  have  contributed  in  regard 
to  the  descent  and  inter-relationship  of  different 
branches  of  the  vegetable  kingdom. 

It  is  by  a  patient  study  of  the  waifs  and  strays 
of  the  vegetation  of  successive  phases  of  the  world's 
history  preserved  in  sedimentary  strata,  that  it  has 
been  possible  to  follow  the  history  of  many  existing 
plants  and  to  establish  links  between  the  present 
and  the  past. 


CHAPTER   IV 

PRESERVATION  OF  PLANTS  AS  FOSSILS 

'  Some  whim  of  Nature  locked  them  fast  in  stone  for  us  after- 
thoughts of  Creation.'     Lowell. 

The  failure  of  the  earlier  naturalists  to  grasp  the 
true  significance  of  fossils  or  even  to  appreciate  their 
nature  is  an  extraordinar}^  fact  when  we  consider  the 
pioneer  work  which  they  accomplished  in  biological 
and  geological  science.  The  following  extract  from 
the  writings  of  so  enlightened  a  man  as  John  Ray 
serves  to  ilkistrate  an  almost  incredible  disinclination 
to  admit  what  seems  to  us  the  obvious.  He  wrote  : — 
'Yet  I  must  not  dissemble  that  there  is  a  Pheno- 
menon in  Nature,  which  doth  somewhat  puzzle  us  to 
reconcile  with  the  prudence  observable  in  all  its 
work,  and  seems  strongly  to  prove,  that  Nature  doth 
sometimes  ludere,  and  delineates  figures,  for  no  other 
end,  but  for  the  ornament  of  some  stone,  and  to 
entertain  or  gratify  our  curiosity,  and  exercise  our 
wits.    This  is,  those  elegant  impressions  of  leaves  and 


CH.  IV]     PRESERVATION   OF  PLANTS  57 

plants  upon  cole- slate,  the  knowledge  of  which, 
I  must  confess  myself  to  leave  to  my  learned  and 
ingenious  friend  Mr  Edward  Lhwyd  of  Oxford.... He 
told  me  that  Mr  Woodward,  a  Londoner,  shewed 
him  very  good  draughts  of  the  common  female  fern, 
naturally  formed  in  cole.... But  these  figures  are  more 
diligently  to  be  observed  and  considered... Dr  Wood- 
ward will  have  them  to  be  the  impressions  of  the 
leaves  of  plants  which  were  there  lodged  at  the  time 
of  the  Deluge '(31). 

The  Mr  Woodward  alluded  to  by  Ray  thus 
expressed  his  views  on  fossils  in  an  Essay  towards 
the  Natural  History  of  the  Earth  : — '  The  whole 
terrestrial  globe  was  taken  all  to  pieces  and  dissolved 
at  the  Deluge,  the  particles  of  stone,  marble,  and 
all  solid  fossils  dissevered,  taken  up  into  the  Avater, 
and  then  sustained  together  with  sea  shells  and  other 
animal  and  vegetable  bodies ;  the  present  earth 
consists  and  was  formed  out  of  that  promiscuous  mass 
of  sand,  earth,  shells,  and  the  rest  falling  down  again, 
and  subsiding  from  the  water '  (32). 

In  the  later  part  of  the  seventeenth  century 
Steno,  a  Dane  by  birth  and  Professor  of  Anatomy  at 
Padua,  by  his  recognition  of  the  identity  of  the  teeth 
in  a  shark's  head,  which  he  had  dissected,  with  some 
fossils  from  Malta  known  as  Glossopetrae,  established 
the  true  nature  of  fossils.  He  also  recognised  a 
certain  orderly  sequence  in  fossiliferous  strata,  and 


58  LINKS  WITH  THE   PAST  [ch. 

in  the  opinion  of  Professor  Sollas  he  is  entitled  to 
be  considered  the  'Father  and  Founder'  of  Geology (33). 

It  was  by  slow  degrees  that  the  early  observers 
freed  themselves  from  the  obsession  that  the  remains 
of  animals  and  plants  in  the  earth's  crust  bear  witness 
to  a  Universal  Deluge  and  are  all  identical  with 
existing  species.  The  possibility  that  some  of  the 
fossil  plants  in  English  strata  might  be  more  clearly 
related  to  forms  now  met  with  in  Avarmer  regions 
was  gradually  realised.  The  publication  of  the 
Origin  of  Species  stimulated  palaeontological 
research,  and  botanists  as  well  as  zoologists  turned 
to  the  investigation  of  extinct  genera  in  search  of 
proofs  of  the  doctrine  of  evolution. 

The  common  occurrence  of  petrified  wood  in 
rocks  of  diflferent  ages  is  well  known.  Fossil  stems 
are  occasionally  found  in  their  natural  position  of 
gi-owth,  the  structural  details  being  rendered  perma- 
nent by  the  deposition  of  siliceous  or  calcareous 
material  from  water  drawn  by  capillarity  into  the 
dead  but  still  sound  tissues.  Petrified  wood  from 
Upper  Jurassic  beds  is  abundant  in  the  Island  of 
Purbeck  ;  an  unusually  long  piece  of  stem  may  be 
seen  in  the  small  town  of  Portland  fixed  to  the  wall 
of  a  house.  Some  of  these  stems  have  been  referred 
by  an  American  author  to  the  Araucarian  family  of 
Conifers,  but  the  structure  is  as  a  rule  hardly  well 
enough  preserved  to  afibrd  satisfactory  evidence  for 


IV]  PRESERVATION  OF   PLANTS  59 

identification.  In  his  Testimony  of  the  RocJcs,  Hugh 
Miller  speaks  of  fossil  wood  from  the  upper  beds  of 
the  Jurassic  system  in  sufficient  abundance  on  the 
beach  at  Helmsdale  in  Sutherlandshire  to  be  collected 
in  cart-loads  ;  it  is  still  easy  to  pick  up  good  speci- 
mens on  the  shingle  beach  a  short  distance  north  of 
Helmsdale,  and  a  recent  microscopical  examination 
showed  that  some  specimens  are  pieces  of  an  Arau- 
carian  tree. 

Impressive  examples  of  petrified  trees  on  a 
large  scale  are  to  be  seen  in  the  United  States, 
in  Arizona  and  the  Yellowstone  Park.  (Frontispiece.) 
In  the  northern  part  of  Arizona  the  country  for  over 
an  area  of  10  square  miles  is  covered  with  tree  trunks, 
some  reaching  200  feet  in  length  and  a  diameter  of 
10  feet.  The  nature  of  the  mineralising  substance  has 
given  rise  to  the  name  Chalcedony  Park  for  this 
Triassic  forest  (34).  A  striking  example  of  one  of  the 
Arizona  trees  is  exhibited  in  the  British  Museum  and 
in  a  neighbouring  case  is  a  splendid  petrified  stem,  9  ft. 
in  height,  of  a  conifer  discovered  in  Tertiary  lavas  in 
Tasmania  (35). 

Figure  6  illustrates  the  preservation  of  a  series 
of  forests  of  Tertiary  age  in  the  mass  of  volcanic 
sediments,  2000  feet  in  thickness,  known  as  Amethyst 
mountain,  in  the  Yellowstone  Park  district.  By  the 
Aveathering  away  of  the  surrounding  volcanic  material 
the  tall  stems  of  the  trees  are  exposed  in  places  on 


Fig.  6.  Section  of  the  north  face  of  Amethyst  Mountain,  Yellow- 
stone Park,  including  upwards  of  2000  ft.  of  strata.  The 
steepness  of  the  slope  is  exaggerated.     (After  W.  H.  Holmes.) 


OH.  IV]      PRESERVATION  OF  PLANTS  61 

the  mountain  sides  like  the  'columns  of  a  ruined 
temple.'  The  height  of  the  river  at  the  foot  of  the 
chff  is  6/00  ft.  above  sea-level  and  the  mountain 
rises  to  a  height  of  9400  ft.  above  the  sea.  In  the 
lower  part  of  the  section  the  volcanic  strata  are  seen 
to  rest  on  a  foundation  of  older  rocks  A,  and  these 
in  turn  were  laid  down  on  the  eroded  surface  of  a 
still  more  ancient  foundation,  J5(36). 

The  section  as  a  whole  affords  a  striking  demon- 
stration of  the  magnitude  of  earth-movements  since 
the  last  of  these  forests  was  buried  below  the 
surface  of  a  sea  in  which  the  volcanic  material  was 
deposited.  The  account  of  the  Yellowstone  Park 
section  recalls  Darwin's  description  in  the  Natural- 
ises Vo I/age (.S7)  of  snow-white  columns  projecting 
from  a  bare  slope,  at  an  altitude  of  7000  ft.  in  the 
Cordillera. 

The  abundance  of  drift  wood  on  the  coasts  of 
some  countries  at  the  present  day  helps  us  to  picture 
the  conditions  under  which  the  remains  of  former 
forests  have  been  preserved.  In  his  Letters  from 
High  Latitudes,  Lord  Dufferin  gives  the  following 
description  of  drift-wood  on  the  shores  of  Spitz- 
bergen  : — '  A  little  to  the  northward,  I  observed, 
lying  on  the  sea-shore  innumerable  logs  of  drift-wood. 
This  wood  is  floated  all  the  way  from  America  by  the 
Gulf  Stream,  and  as  I  walked  from  one  huge  bole 
to   another,   I   could   not  help   wondering  in   what 


62  LINKS  WITH  THE  PAST        [ch.  iv 

primeval  forest  each  had  grown,  what  chance  had 
originally  cast  them  on  the  waters,  and  piloted 
them  to  this  desert  shore 'os).  A  photograph  re- 
produced in  Amundsen's  book  on  The  North  West 
Passage  shows  the  beach  on  the  Alaskan  coast 
strewn  with  drifted  timber (39).  For  the  accompanying 
photograph  (Fig.  7)  of  the  flood-plain  of  the  Colorado 
River (40),  I  am  indebted  to  Professor  MacDougal  of 
the  Desert  Research  Laboratory  at  Tucson,  Arizona, 
who  in  a  recent  letter  writes,  '  During  times  of  high- 
water  a  thin  sheet  of  flood  covers  the  flat  for  many 
miles  and  bears  drift-wood  so  thickly  that  it  is 
difficult  to  push  a  boat  through  it.'  The  drift-wood 
consists  of  poplar,  willow,  pine,  and  juniper,  '  the  last 
two  have  been  brought  from  the  upper  river,  from 
as  far  away  as  a  thousand  miles.'  A  picture  such  as 
this  affords  an  admirable  example  of  the  wealth 
of  material  available  for  preservation  in  a  fossil  state. 
It  is  only  in  the  minority  of  cases  that  the 
accidents  of  preservation  of  fragments  of  ancient 
floras  have  given  us  the  means  of  investigating  the 
internal  structure  of  the  plant  organs.  It  is  far  more 
frequently  the  case  that  fossil  plants  are  represented 
only  by  a  carbonised  film  on  the  surface  of  a  piece  of 
shale  or  other  rock  :  the  actual  substance  of  the 
plant  has  been  converted  into  a  thin  layer  of  coal, 
and  though  the  venation  and  other  surface-features 
may  be  clearly  revealed,  the  internal  tissues  have 


Fig.  7.  Flood-plain  of  the  delta  of  Kio  Colorado.  The  hills  in 
the  background  are  25  miles  distant.  (From  a  photograph  by 
Prof.  MacDougal.) 


64  LINKS  WITH  THE  PAST  [ch. 

been  destroyed.  If  a  lump  of  clay  containing  a 
piece  of  fern  frond  is  heated,  the  result  is  an  im- 
pression of  the  leaf  on  the  hardened  matrix  and  a 
coaly  substance  in  place  of  the  plant  substance.  It 
is  occasionally  possible  by  detaching  a  piece  of  the 
black  film  from  a  fossil,  and  heating  it  with  nitric 
acid  and  chlorate  of  potash  and  then  dipping  it  in 
ammonia,  to  obtain  a  transparent  preparation  suitable 
for  microscopical  examination  of  the  cell-outlines 
of  the  superficial  layer  of  the  leaf  or  other  plant- 
fragment.  This  method  of  examination,  used  by 
several  students  of  fossil  plants  and  with  conspicuous 
success  by  Professor  Nathorst  of  Stockholm,  often 
affords  valuable  aids  to  identification. 

Pieces  of  plants  embedded  in  sandy  sediment, 
if  not  preserved  by  petrifaction,  that  is  by  the 
introduction  into  the  tissues  of  some  siliceous 
or  calcareous  solution,  gradually  decay  and  their 
fragmentary  remains  may  be  washed  away  by 
percolating  watei',  leaving  a  hollow^  mould  in  the 
gradually  hardening  sediment,  which  is  afterwards 
filled  with  sand  or  other  material.  The  plant  itself 
is  destroyed,  but  a  cast  is  taken  which  in  the  case 
of  fine-grained  sediments  reproduces  the  form  and 
surface-pattern  of  the  original  specimen.  The  in- 
crustation of  plants  by  the  falsely  named  petrifying 
springs  of  Knaresborough  and  other  places  illustrate 
another  method  of  fossilisation. 


IV] 


PRESERVATION   OF   PLANTS 


65 


Plants  which  owe  their  preservation  to  amber 
occur  both  as  incrustations  and  petrifactions.  This 
fossil  resin  occurs  in  Tertiary,  Cretaceous,  and 
Jurassic  rocks  ;  the  amber  found  in  abundance  on 
the  Baltic  coast  near  Danzig  and  occasionall}^  picked 
up  on  the  beach  in  Norfolk  and  Suffolk  comes  from 


Fig.  8.     Flower  of  Cinnamoum  prototypum  Conw.  preserved  in 
amber.      x  10.     (After  Conwentz.) 

beds  of  Tertiary  age.  Pieces  of  Pine-wood  have  been 
described  from  the  Baltic  beds  in  which  the  tissues 
are  perfectly  preserved  as  the  result  of  the  conversion 
into  amber  of  the  resinous  secretion  which  permeates 
their  cells  :  in  this  case  the  amber  is  a  petrifying 
s.  5 


66  LINKS  WITH   THE   PAST  [ch. 

agent.  More  frequently  the  preservation  is  due  to 
incrustation  ;  as  resin  trickled  down  the  stems  of  the 
Tertiary  pines  from  an  open  wound,  flowers  and 
leaves,  blown  by  the  wind  on  to  the  sticky  surface, 
were  eventually  sealed  up  in  a  translucent  case  of 
amber.  Though  the  actual  substance  may  have  gone, 
the  mould  which  remains  exhibits  in  wonderful  per- 
fection each  separate  organ  of  a  flower  or  the 
delicate  hair-clusters  on  the  surface  of  a  leaf.  The 
flower  represented  in  Fig.  8,  a  species  of  Cinnamon, 
is  one  of  several  specimens  described  by  tlie  authors 
of  a  monograph  of  Tertiary  plants  in  the  Baltic 
amber{4i). 

The  fragments  of  plants  preserved  in  nodules  of 
calcareous  rock  occasionally  met  with  in  some  of  the 
Lancashire  and  Yorkshire  coal-scams  are  perhaps 
the  most  striking  examples  of  the  possibilities  of 
petrifaction.  By  cutting  sections  of  these  nodules 
and  grinding  them  to  a  transparent  thinness,  the 
most  delicate  tissues  of  Carboniferous  plants  are 
rendered  accessible  to  investigation  under  the  high 
power  of  a  microscope.  As  our  attention  is  absorbed 
by  the  examination  of  the  details  of  cell-structure 
it  is  easy  to  forget  that  the  section  has  not  been 
cut  from  a  living  plant,  but  from  the  twig  of  a 
tree  which  grew  in  the  forests  of  the  Coal  age.  The 
preservation  is  such  as  to  enable  us  not  only  to 
describe   the    anatomy    of   these    extinct    types    of 


IV]  PRESERVATION  OF  PLANTS  67 

vegetation,  but,  by  the  application  of  the  knowledge 
of  the  relation  between  the  structure  of  the  plant- 
machine  and  its  functions  gained  by  a  study  of  living 
species,  it  is  possible  in  some  degree  to  picture  the 
plants  of  the  Coal  period  as  living  organisms  and 
to  see  in  the  structural  framework  a  reflection  ot 
external  environment.  The  recognition  in  the  general 
architectural  plan  of  the  Palaeozoic  plants,  as  in 
many  of  the  finer  anatomical  features,  of  the  closest 
resemblance  to  plants  of  the  modern  world  produces 
an  almost  overwhelming  sense  of  continuity  between 
the  past  and  the  present. 

The  plants  of  the  Palaeozoic  period,  though  often 
diffbring  considerably  from  those  of  the  same  class 
in  the  floras  of  to-day,  exhibit  a  remarkably  high  type 
of  organisation.  Some  of  the  most  abundant  trees  in 
the  forest  of  the  Coal  age  are  decidedly  superior 
in  the  complexity  of  their  structure,  as  also  in 
size,  to  modern  survivals  of  the  same  stock.  On 
the  other  hand,  it  must  be  remembered  that  Mono- 
cotyledons and  Dicotyledons  which  now  occupy  the 
highest  place  in  the  hierarchy  of  plants  have  left  no 
sign  of  their  existence  in  any  of  the  Palaeozoic  strata. 
The  greater  size  of  some  of  the  Palaeozoic  plants, 
and  in  some  respects  the  more  advanced  stage  of 
evolution  which  they  represent  as  compared  with 
their  nearest  relatives  of  the  present  era,  must  be 
considered  in  relation  to  their  more  important  and 

5—2 


68  LINKS  WITH  THE   PAST  [ch. 

relatively  higher  position  in  the  plant-world  than 
that  which  is  now  held  by  their  diminutive  de- 
scendants. It  is,  however,  impossible  to  get  away 
from  the  conclusion  that  the  oldest  Palaeozoic  floi'a 
of  which  we  have  an  intimate  knowledge  must  be 
the  product  of  development  of  an  age  which  is 
represented  by  a  chapter  in  the  history  of  the  plant 
kingdom  at  least  as  far  removed  from  the  beginning 
as  it  is  separated  from  the  chapter  now  being  written. 
Examples  might  be  quoted  in  illustration  of  the  risks 
attending  the  determination  of  fossils  by  means  of 
external  features  alone,  but  it  may  suffice  to  mention 
the  case  of  a  specimen  originally  described  as  a 
fragment  of  a  Cretaceous  Dinosaur  under  the  name 
AacJienosmiriis  multidens.  By  the  examination  of 
thin  sections  this  supposed  bone  was  shown  to  be 
a  piece  of  Dicotyledonous  wood  (42).  The  methods  of 
preservation  of  plants  as  fossils  are  numerous  and 
varied  and  the  few  examples  selected  give  but  an 
incomplete  idea  of  the  subject :  for  a  fuller  treatment 
of  fossilisation  the  reader  is  referred  to  more  technical 
treatises  (48  vol.  i.). 

The  employment  of  fossil  plants  as  '  Thermometers 
of  the  ages '  is  a  branch  of  Palaeobotany  to  which  a 
passing  allusion  may  be  permitted  though  it  is  only 
indirectly  connected  with  the  main  question.  As 
one  of  the  most  interesting  examples  of  changed 
climatic  conditions  revealed  by  a  study  of  fossil  plants, 


IV]  PRESERVATION  OF  PLANTS  69 

reference  may  be  made  to  the  wealth  of  material 
collected  within  the  Arctic  circle.  The  problems 
suggested  by  the  discovery  of  plants  in  rocks  of 
various  ages  in  North  Siberia,  Spitzbergen,  Franz 
Josef  Land,  Bear  Island,  Greenland,  and  in  many 
other  localities  in  the  far  north  are  too  difficult 
and  far-reaching  to  be  discussed  in  these  pages.  In 
the  Cretaceous  and  Tertiary  strata  of  the  west  coast 
of  Greenland  and  Disco  Island  from  69°  to  72°  north 
latitude,  to  refer  only  to  one  case,  a  great  number 
of  plants  have  been  obtained  by  several  of  the  earlier 
Arctic  explorers  and  more  recently  by  members  of 
one  of  the  Peary  Expeditions.  At  the  present  day 
on  the  fringe  of  land  on  the  western  edge  of  Green- 
land which  is  not  permanently  covered  with  ice, 
a  considerable  number  of  herbaceous  plants  are  able 
to  exist  and  to  produce  seed  during  their  concentrated 
period  of  development ;  while  trees  are  represented 
only  by  a  few  low-growing  shrubs  such  as  the  dwarf 
Juniper.  In  places  accessible  to  investigation  beyond 
the  ice-covered  hills  of  northern  Greenland  the  rocks 
have  been  shown  to  consist  of  Cretaceous  and  Tertiary 
sediments  containing  fossil  plants  associated  with 
seams  of  coal.  From  these  beds  numerous  Dicotyle- 
dons have  been  obtained,  some  of  them  almost 
identical  with  living  species  characteristic  of  sub- 
tropical or  tropical  countries.  In  the  lowest  of  the 
Cretaceous  series  no  Dicotyledons  have  been  found, 


70  LINKS  WITH  THE  PAST         [ch.  iv 

but  flowering  plants  are  abundant  in  the  higher 
Cretaceous  rocks.  Allowing  for  the  fact  that  closely 
allied  species  are  often  able  to  live  under  very 
different  climatic  conditions,  there  can  be  no  doubt 
that  the  Cretaceous  and  Tertiary  floras  of  Greenland 
indicate  an  average  temperature  considerably  higher 
than  that  which  now  prevails  in  the  warmest  parts 
of  the  British  Isles. 

In  the  far  south  a  fairly  rich  Jurassic  flora  has 
recently  been  discovered  by  the  members  of  a 
Swedish  Antarctic  expedition  in  Graham's  Land  in 
latitude  63°-15  S.  and  longitude  57°  W.,  which  in  its 
general  facies  bears  a  close  resemblance  to  the 
Jurassic  flora  of  Yorkshire. 

Although  the  great  majority  of  the  records  of 
ancient  plants  are  difficult  to  interpret  by  reason 
of  imperfect  preservation  and  because  of  the  frequent 
separation  of  leaves,  stems,  and  reproductive  organs, 
the  student  who  tries  to  piece  together  the  disjecta 
membra  of  the  floras  of  the  past  shares  the  opinion 
expressed  by  the  late  Marquis  of  Saporta, — '  Si  Ton 
s'attache  a  les  dechiffrer,  on  oublie  bien  vite  la 
singularite  des  caracteres,  et  le  mauvais  t^tat  des 
pages.  La  pensee  se  l^ve,  les  idees  se  developpent, 
le  manuscrit  se  deroule  ;  c'est  la  tombe  qui  parle  et 
livre  son  secret.' 


CHAPTER  V 

FERNS;  THEIR  DISTRIBUTION   AND   ANTIQUITY 

'  It  has  been  shown  that  certain  forms  persist  with  very  little 
change,  from  the  oldest  to  the  newest  fossiliferous  formations ;  and 
thus  show  that  progressive  development  is  a  contingent,  and  not 
a  necessary,  result  of  the  nature  of  living  matter.'     Huxley. 

The  Ferns  as  a  whole  represent  a  section  of  the 
vegetable  kingdom  which  traces  its  ancestry  as  far 
into  the  past  as  any  group  of  plants.  Impressions  of 
leaves  on  the  shales  of  the  Coal-measures  and  on 
rocks  of  the  earlier  Devonian  period  are  hardly 
distinguishable  in  form  and  in  the  venation  and 
shape  of  the  leaflets  from  the  finely  divided  fronds 
of  modern  ferns.  Until  a  few  years  ago  these 
Palaeozoic  fossils  were  generally  regarded  as  true 
ferns,  and  it  was  believed  that  ferns  played  a  con- 
spicuous part  in  the  vegetation  of  the  earliest  periods, 
of  which  we  have  any  botanical  knowledge.  Con- 
clusions based  on  external  form  must  frequently  be 


n  LINKS  WITH   THE  PAST  [ch. 

revised  in  the  light  of  more  trustworthy  evidence. 
It  was  shown  in  the  later  part  of  the  nineteenth 
centur}^  by  the  late  Professor  Williamson  of  Man- 
chester, whose  researches  into  the  plants  of  the 
Coal  age  shed  a  flood  of  light  on  the  ancestry  and 
inter-relationship  of  many  existing  plants,  that  some 
of  the  fern-like  leaves  which  have  long  been  familiar 
to  those  who  search  among  the  shales  of  the  refuse 
heaps  of  collieries,  were  borne  on  stems  differing  in 
anatomical  features  from  those  of  any  known  fern. 
The  investigation  of  the  structure  of  the  leaves  and 
their  supporting  stems  led  to  the  recognition  of 
certain  extinct  genera  of  Palaeozoic  plants  of  excep- 
tional interest,  to  which  the  term  generalised  type  is 
aptly  applied.  Associated  with  anatomical  and  other 
characters  such  as  we  now  regard  as  the  attributes 
of  ferns,  these  plants  exhibit  other  features  not  met 
with  in  modern  ferns  but  characteristic  of  a  group  of 
seed-bearing  plants  known  as  the  Cycads.  Recent 
research  has  revealed  the  existence  of  several  such 
generalised  types  which,  by  their  combination  of 
characters  now  met  with  in  distinct  sub-divisions 
of  the  plant-kingdom,  clearly  indicate  the  derivation 
of  Ferns,  and  Cycads  as  we  know  them  to-day,  from 
a  common  stock.  It  was  in  the  first  instance  by 
means  of  anatomical  evidence — obtained  by  the 
microscopical  examination  of  sections  of  petrified 
fragments  of  stems  and  leaves — that  the  generalised 


V]  FERNS  73 

nature  of  these  Palaeozoic  plants  was  recognised. 
Nothing  was  known  as  to  the  reproductive  organs. 
Ferns  as  now  represented  in  the  floras  of  the 
world  are  essentially  seed-less  plants.  As  the  author 
of  Hudihras  wrote  : 

'  Who  would  believe  what  strange  bugbears 
Mankind  creates  itself,  of  fears? 
That  spring  like  fern,  that  insect  weed, 
Equivocally,  without  seed.' 

The  reproductive  organs  or  spores  borne  on  the 
fronds  of  a  fern  produce,  on  germination,  a  thin 
green  structure,  known  as  the  prothallus,  less  than 
an  inch  in  length  :  this  bears  the  sexual  organs,  and  as 
the  result  of  the  union  of  the  male  and  female  cells, 
the  embryo  fern-plant  begins  its  existence  as  a  parasite 
on  the  inconspicuous  prothallus,  until  after  unfolding 
its  first  green  leaf  and  thrusting  a  slender  root  into 
the  ground,  it  starts  its  career  as  an  independent 
organism \  In  this  life-cycle  the  seed  plays  no 
part. 

It  is  noteworthy  that  the  absence  of  any  indication 
of  spore-capsules  and  spores,  in  the  case  of  some  of 
the  supposed  fern  leaves  from  the  Coal-measures, 
caused  some  suspicion  in  the  mind  of  an  Austrian 
Palaeobotanist  as  to  the  right  of  such  specimens  to 

^  The  life-history  of  a  Fern  is  clearly  described  by  Prof.  Bower 
in  a  recent  volume  in  this  series. 


74  LINKS  WITH   THE   PAST  [ch. 

be  classed  among  the  ferns.  This  opinion,  based  in 
the  first  place  on  negative  evidence  and  but  little 
regarded  by  other  authors,  has  in  recent  years 
been  proved  correct.  In  1904  a  paper  was  read 
before  the  Royal  Society  by  Professor  Oliver  and 
Dr  Scott(43)  in  which  evidence  was  brought  forward 
pointing  to  the  conclusion  that  one  of  these 
generalised  plants  bore  true  seeds.  Subsequently 
Dr  Kidston  published  an  account  of  some  specimens 
of  another  of  these  Palaeozoic  plants  in  which  was 
actually  shown  an  organic  connexion  between  un- 
doubted seeds  and  pieces  of  a  fern-like  frond  (44). 
Without  entering  into  further  details,  these  and 
similar  discoveries  may  be  summarised  as  follows  : — 
Many  of  the  supposed  Fern -fronds  of  Palaeozoic 
age,  particularly  those  characteristic  of  the  Coal- 
measures,  are  the  leaves  of  plants  which  in  their 
anatomical  characters  combined  features  now  shared 
by  true  Ferns  and  by  the  Cycads.  The  reproductive 
organs  of  these  Palaeozoic  genera  differed  widely 
from  those  of  existing  ferns  ;  the  male  organs,  while 
not  unlike  the  spore-capsules  and  spores  of  certain 
ferns,  recall  the  male  organs  of  living  Conifers  and 
Cycads,  and  the  female  organs  were  represented  by 
seeds  of  a  highly  complex  form.  These  seed-bearing 
plants  have  been  called  Pteridosperms,  a  name 
which  expresses  the  combination  of  fern-like  features 
with   one   of   the   distinguishing    attributes    of   the 


v]  FERNS  75 

higher  plants,  namely  the  possession  of  seeds.  The 
ancestors  of  Pteridosperms  are  as  yet  unknown  ;  it 
is,  however,  reasonable  to  assume  that  there  existed 
in  some  pre-Carboniferous  epoch  a  group  of  simple 
plants  from  which  both  Ferns  and  Pteridosperms 
were  derived.  In  the  forests  of  the  Coal  age  true 
Ferns  probably  occupied  a  subordinate  position  in 
relation  to  the  Pteridosperms. 

The  question  of  the  relationship  between  different 
families  of  recent  ferns  and  the  older  known  fossil 
members  of  the  group  is  beyond  the  scope  of  this 
book.  Evidence  has  been  discovered  in  recent  years 
which  warrants  the  statement  that,  although  none  of 
those  Carboniferous  ferns  were  generically  identical 
with  existing  forms,  they  very  clearly  foreshadowed 
some  of  those  structural  features  which  characterise 
more  than  one  family  of  present-day  Ferns.  The 
records  of  the  older  Mesozoic  formations  afford 
abundant  evidence  of  the  existence  of  certain  types 
of  Ferns  showing  a  very  close  resemblance  to  recent 
species. 

An  enquiry  into  the  geographical  distribution  of 
living  Ferns  reveals  facts  of  special  interest  in 
connexion  with  the  relative  antiquity  of  different 
genera  and  families.  The  wide  distribution  of  the 
Bracken  fern  has  already  been  referred  to  :  it  is 
abundant  in  Tasmania ;  its  vigour  in  the  island 
is  well  illustrated  by  Mr  Geoffrey  Smith's  statement 


76 


LINKS  WITH  THE  PAST 


[CH. 


Fig,   9.     Osmunda  regalis  Linu.     Fertile  frond,     (f  nat.  size.) 


v]  FERNS  11 

that  constant  attention  is  necessary  to  keep  it  from 
invading  newly  opened  country (45).  On  Mount  Ophir 
in  the  Malay  Peninsula  the  cosmopolitan  bracken 
occurs  in  association  with  the  two  genera  Matonia 
and  Dipteris,  ferns  which  are  among  the  most  striking 
examples  of  links  with  a  remote  past  and  have  a 
restricted  geographical  range.  With  Osmunda  re- 
galis,  the  Royal  Fern,  the  Bracken  is  conspicuous 
in  the  marsh  vegetation  of  the  Bermudas ;  it  flourishes 
on  the  Atlas  INIountains,  in  the  Canary  Islands,  in 
Abyssinia,  on  Mt  Kenia,  in  British  East  Africa,  in 
the  Himalayas,  and  is  in  fact  generally  distributed  in 
the  tropics  in  both  the  north  and  south  temperate 
zones. 

The  Royal  Fern  (Fig.  9)  is  another  British  species 
with  a  wide  distribution  ;  it  occurs  in  Northern  Asia 
and  in  North  America  ;  it  is  common  in  the  Siberian 
forests  and  lives  in  several  tropical  countries,  ex- 
tending to  Southern  India  and  Cape  Colony,  and  in 
South  America  it  is  represented  by  a  closely  allied 
species.  Though  at  the  present  day  Osmunda  regalis 
is  one  of  the  rare  English  Ferns,  its  occurrence  in  the 
submerged  forest-beds  round  our  coasts  and  in  pre- 
Glacial  beds  points  to  its  former  abundance  in  the 
British  area  generally.  The  Royal  Fern  is  a  member 
of  a  family  now  represented  by  two  genera,  Osmunda 
and  Todea. 

With  the  exception  of  Todea  harhara,  with  its 


78  LINKS  WITH  THE  PAST  [ch. 

large  spreading  fronds  and  a  short  root-covered  stem, 
which  occurs  in  Australia  and  Cape  Colony,  all  the 
species  of  this  genus  are  filmy  ferns  with  semi- 
transparent  fronds  adapted  to  a  moisture-laden 
atmosphere.  -O410  filmy  opooion  of  Todea  is  repre- 
sented in  tho  Brititfli  lima  b)  Toden  mdwans  in 
the  Killatne)  di.'^tiict  uf  Ireland  ;  but  the  maximum 
development  of  the  genus  is  in  New  Zealand. 

Todea  harhara  affords  an  instance  of  discontinuous 
distribution  ;  it  was  no  doubt  once  widely  spread  in 
circumpolar  regions  and  noAV  survives  only  in  South 
Africa  and  in  Australia. 

There  are  satisfactory  reasons  for  regarding  the 
Bracken  Fern,  with  its  world-wide  range  in  present- 
day  floras,  as  a  comparatively  modern  species  now  in 
full  vigour.  Its  anatomical  and  other  features  are 
consistent  with  the  view  that  it  is  a  late  product  of 
evolution,  and  as  yet  no  indication  has  been  given  by 
the  records  of  the  rocks  of  an  ancient  lineage.  The 
Osmunda  family,  on  the  other  hand,  is  undoubtedly 
an  extremely  old  branch  of  the  fern  group.  A  com- 
parison of  the  Royal  Fern  with  the  Bracken  shows 
that  their  stems  are  constructed  on  very  different 
plans,  and  we  have  good  reasons  for  speaking  of  the 
structural  peculiarities  of  the  former  as  those  of 
a  more  primitive  type.  Moreover,  the  discontinuous 
geographical  range  of  some  members  of  the  Osmunda 
family  is  in  itself  an  indication  of  antiquity.     There 


V]  FERNS  79 

is  another  point  which  may  have  a  bearing  in  this 
question  of  antiquity,  namely  the  fact  that  the  spores 
of  Osmunda  are  green  and  do  not  possess  the  powers 
of  indurance  inherent  in  the  spores  of  the  majority  of 
ferns  which  are  not  green.  It  has  recently  been  con- 
tended by  Professor  Campbell  of  Stanford  University 
that  the  delicate  green  spores  of  the  Liverworts, 
plants  closely  allied  to  the  Mosses,  constitute  an 
argument  in  favour  of  the  antiquity  of  these  plants  (46). 
Certain  Liverworts  are  cosmopolitan  in  their  range, 
e.g.  the  genera  Riccia  and  Marchantia. 

If  certahi  genera  are  widely  distributed,  notwith- 
standing the  fact  that  their  reproductive  cells,  by 
which  dispersal  is  effected,  are  ill-adapted  to  withstand 
unfavourable  conditions  or  to  endure  prolonged 
desiccation,  it  would  seem  reasonable  to  conclude 
that  their  emigration  has  been  accomplished  slowly 
and  with  difficulty.  Ferns  such  as  Osmunda,  with 
green  and  short-lived  spores,  would  thus  be  handi- 
capped in  competition  with  other  genera  provided 
with  more  efficient  means  of  dispersal  and  better 
equipped  for  the  vicissitudes  of  travel. 

The  inferences  as  to  antiquity  deduced  from  a 
study  of  the  existing  species  of  Osmunda  and  Todea 
receive  striking  confirmation  from  the  testimony  of 
fossils.  Some  of  the  oldest  known  Palaeozoic  ferns, 
though  differing  too  widely  from  the  existing  Osmundas 
and  Todeas  to  be  included  in  the  same  family,  afford 


80  LINKS   WITH  THE   PAST  [ch. 

distinct  glimmerings  of  Osmundaceous  characters, 
which  at  a  hiter  period  became  individiiahsed  in 
the  direct  ancestors  of  the  modern  forms.  Our 
knowledge  of  the  past  history  of  the  Osmnnda  famil}^ 
has  recently  been  considerably  extended  and  })laced 
on  a  firmer  basis  by  the  researches  of  I)r  Kidston 
and  Professor  Gwynne-Yaughan.  These  authors  have 
recognised  in  some  exceptionally  well-preserved  fern- 
stems  from  Permian  rocks  in  Russia,  anatomical 
features  which  point  unmistakably  to  close  rela- 
tionship Avith  the  recent  members  of  the  family (47) (48). 

Passing  higher  up  the  geological  series,  fertile 
fern  fronds  with  spore-capsules  and  spores  practically 
identical  with  those  of  Osmnnda  have  been  found  in 
the  Jurassic  plant-beds  of  Yorkshire  and  in  rocks 
of  approximately  the  same  age  in  many  parts  of  the 
world.  From  Jurassic  strata  in  New  Zealand  a 
petrified  fern-stem  has  been  described  (OsmuudUes 
Dnnlo}ji),  almost  identical  in  structure  with  the 
surviving  species.  Cretaceous  and  Tertiary  examples 
of  similar  ferns  might  be  cpioted  ;  but  enough  lias 
been  said  to  establish  the  claim  of  the  Royal  Fern 
and  other  members  of  the  Osmunda-family  to  an 
ancestry  which  possibly  extends  even  farther  back 
than  that  of  any  other  existing  family  of  Ferns. 

A  brief  reference  may  be  made  to  another  fern  now 
represented  by  several  species  widely  disseminated 
in  tropical  and  sub-tropical  countries.    The  genus 


V] 


FERNS 


81 


Gleichenia  occurs  abundantly  in  the  warmer  regions 
of  both  the  Old  and  New  World.  The  fronds  may 
usually  be  recognised  by  their  habit  of  growth 
(Fig.    10) ;    in    several    species    the    main    axis    is 


Fig.  10.     Gleichenia  dicarpa  Br.     {h  nat.  size.) 


repeatedly   forked   and   a   small   bud    between    the 

divergent  branches  of  the  forks  forms  a  characteristic 

feature.     The  leaflets  are  either  long  and  narrow 

s  6 


82  LINKS  WITH  THE  PAST  [ch. 

like  the  teeth  of  a  comb  or  short  and  bhmtly  rounded. 
Moreover  the  anatomy  of  the  creeping  stem  affords 
a  ready  means  of  identification.  We  have  satisfactory 
evidence  of  the  occurrence  of  Gleichenia  in  European 
floras  during  both  the  Jurassic  and  Cretaceous 
periods.  Numerous  fragments  of  plants  were  obtained 
some  years  ago,  not  far  from  Brussels,  from  the  Wealden 
strata  in  which  the  famous  skeletons  of  Iguanodon 
were  discovered.  Visitors  to  the  Natural  History 
Museum  in  Brussels  are  no  doubt  familiar  with  the 
skeletons  of  this  enormous  herbivorous  animal :  in 
the  same  gallery  are  exhibited  the  remains  of  the 
fossil  plants  from  the  Iguanodon  beds.  Some  of 
these  fragments  are  pieces  of  fern  fronds  identical 
in  form  with  those  of  existing  Gleichenias.  The 
microscopical  examination  of  some  exceptionally  well 
preserved  fragments  of  Wealden  stems  discovered  by 
Prof.  Bommer  of  Brussels  enabled  him  to  recognise 
the  Gleichenia  type  of  structure  and  thus  to  confirm 
the  inconclusive  evidence  furnished  by  fragmentary 
leaves.  The  most  interesting  records  in  regard  to 
the  former  occurrence  of  Gleichenia  in  Northern 
Europe  we  owe  to  the  late  Oswald  Heer  of  Zurich, 
who  has  described  many  examples  of  Gleichenia 
fronds  from  rocks  of  Lower  Cretaceous  age  in 
Disco  Island  on  the  west  coast  of  Greenland  in 
latitude  70°  N.  The  same  type  of  fern  is  recorded 
also  from  upper  Jurassic  beds  in  the  north-east  of 


v]  FERNS  83 

Scotland,  in  the  Wealden  rocks  of  Sussex,  as  well  as 
from  other  European  localities.  It  is  clear  that  the 
Gleichenia-family,  no  longer  represented  in  north 
temperate  floras,  was  in  the  Jurassic  period,  and 
especially  in  the  early  days  of  the  Cretaceous  period, 
widely  spread  in  Europe,  extending  well  within  the 
Arctic  circle.  It  may  be  that  the  original  home  of 
Gleichenia  was  in  the  far  North  at  a  time  when 
climatic  conditions  were  very  different  from  those 
which  now  prevail.  Gleichenia,  like  many  other 
northern  plants,  retreated  to  more  southern  regions 
where,  in  the  warmer  countries  of  the  world,  many 
species  still  flourish  widely  separated  in  space  and 
time  from  the  place  of  their  birth. 

The  ferns  so  far  mentioned  have  a  more  or  less 
extended  distribution  at  the  present  day.  In  the 
case  of  Pteridium  aquilhmm,  the  cosmopolitan 
Bracken  Fern,  wide  range  Avould  seem  to  be  corre- 
lated with  comparatively  recent  origin ;  on  the 
other  hand,  the  facts  of  palaeobotany  show  that 
the  wide  distribution  of  Osmunda,  a  type  of  fern 
which  differs  in  many  important  respects  from 
members  of  the  family  (Folypodiaceae)  to  which 
the  Bracken  belongs,  is  not  inconsistent  with  an 
exceptionally  ancient  family-history.  There  are, 
however,  certain  genera  of  ferns  which  afford 
remarkable  examples  of  restricted  geographical 
distribution    associated  with   great   antiquity.     The 

6—2 


84  LINKS  WITH  THE   PAST  [ch. 

island  of  Juan  Fernandez,  420  miles  oflf  the  coast 
of  Chili,  the  home  for  four  years  of  Alexander 
Selkirk  (to  whose  adventures  we  owe  Defoe's 
creation  of  Robinson  Crusoe),  is  interesting  also 
from  a  botanical  point  of  view.  The  vegetation  of 
this  oceanic  island,  20  square  miles  in  area  with 
basaltic  cliffs  rising  to  a  height  of  3000  ft.  above 
the  sea,  includes  more  than  40  species  of  ferns, 
eight  of  which  occur  nowhere  else.  One  of  these 
endemic  ferns  is  Thyrso2:tteris  elegans,  the  only 
representative  of  the  genus ;  it  is  readily  distinguished 
by  its  large  and  graceful  fertile  fronds,  examples  of 
which  may  occasionally  be  seen  on  a  plant  of  this 
species  in  the  Royal  Gardens  at  Kew  :  the  sporangia 
are  produced  in  circular  cups  which  replace  the 
ordinary  leaflets  on  the  lower  branches  of  the  frond 
and  hang  from  the  short  axis  like  miniature  clusters 
of  grapes.  It  is  noteworthy  that  among  the  frag- 
mentary remains  of  the  fern  vegetation  of  the  Jurassic 
flora  in  England  and  in  other  parts  of  Europe 
specimens  occur  with  fertile  segments  practically 
identical  with  those  of  the  Juan  Fernandez  species. 
Students  of  fossil  plants  are  occasionally  led  away 
by  the  temptation  to  identify  imperfect  specimens 
with  rare  existing  species  to  which  they  exhibit  a 
superficial  resemblance,  and  this  is  well  illustrated 
by  tlie  frequent  use  of  the  generic  name  Thyrsopteris 
for  Jurassic  and  Lower  Cretaceous  ferns  which  are 


v]  FERNS  85 

too  imperfect  to  be  determined  with  any  degree  of 
certaint}^  We  have,  however,  satisfactory  grounds 
for  the  assertion  that  the  Juan  Fernandez  fern 
affords  a  striking  confirmation  of  the  truth  of 
Darwin's  dictum  that  'Rarity,  as  geology  tells  us, 
is  the  precursor  to  extinction.'  In  this  remote  oceanic 
island,  for  reasons  which  we  cannot  explain,  there 
lingers  an  isolated  type  which  belongs  to  another  age. 
The  following  passage,  which  forms  a  fitting 
introduction  to  an  account  of  two  other  genera  of 
ancient  ferns,  is  taken  from  a  description  of  an 
ascent  of  Mount  Ophir  in  the  Malay  Peninsula  by  Dr 
A.  R.  Wallace  in  his  well-known  book  on  the  Malay 
Archipelago  : — '  After  passing  a  little  tangled  jungle 
and  swampy  thickets,  we  emerged  into  a  fine  lofty 
forest.... We  ascended  steadily  up  a  moderate  slope 
for  several  miles,  having  a  deep  ravine  on  the 
left.  We  then  had  a  level  plateau  or  shoulder  to 
cross,  after  which  the  ascent  was  steeper  and  the 
forest  denser  till  we  came  out  upon  the  Padang- 
Batu,  or  stone-field.... We  found  it  to  be  a  steep 
slope  of  even  rock,  extending  along  the  mountain 
side  farther  than  we  could  see.  Parts  of  it  were 
quite  bare,  but  where  it  was  cracked  and  fissured 
there  grew  a  most  luxuriant  vegetation,  among  which 
the  pitcher  plants  were  the  most  remarkable.... A  few 
coniferae  of  the  genus  Dacrydium  here  first  appeared, 
and  in  the  thickets,  just  above  the  rocky  surface, 


LINKS  WITH  THE   PAST 


[CH. 


we  walked  through  groves  of  those  splendid  ferns, 
Dipteris  Horsjieldu  and  Matonia  2)(^ctmata,  which 


Fig.   11.     Matonia  2)ectinata.     A  group  of  plants  in  a  wood  on 
Gunong  Tundok,  Mount  Ophir.     (Photograph  by  Mr  A.  G.  Tansley.) 

bear  large  spreading  fronds  on  slender  stems,  6  or 
8  feet  high '(49). 


V]  FERNS  87 

The  two  genera  Matonia  and  Dipteris  afford 
exceptionally  striking  examples  of  survivals  from 
the  past.  Matonia  is  represented  by  two  species, 
Matonia  jyectinata  (Fig.  11),  which  grows  abundantly 
on  the  upper  slopes  of  Padang  Batu  in  dense  thickets 
on  the  rock  faces  where,  as  Mr  Tansley  states,  its 
associates  are  a  species  of  Gleichenia,  Dipteris, 
and  a  little  Pterldmm  aquilimim  (Bracken  Fern). 
3Iafoma  pectinata  occurs  also  on  Bornean  mountains 
at  an  altitude  of  over  3000  ft.  and  descends  to  the 
coast  on  some  of  the  Malay  islands.  The  other 
species  of  the  genus,  Matonia  sarmeutosa,  has  so 
far  been  found  in  one  locality  only,  Mak,  Sarawak, 
where  it  was  discovered  by  Mr  Charles  Hose. 
Matonia  pectinata  has  a  creeping  stem  covered  with 
a  thick  felt  of  brown  hairs  bearing  tall  fan-shaped 
fronds  divided  into  numerous  comb-like  branches 
thickly  set  with  narrow  linear  leaflets  on  Avhich 
circular  clusters  of  spore-capsules  are  sparsely  scat- 
tered. In  some  respects  Matonia  is  unlike  other 
ferns  ;  the  fronds  constitute  a  striking  feature,  and 
the  anatomy  of  the  stem  is  still  more  distinctive. 
In  the  form,  development,  and  arrangement  of  the 
sporangia  (spore-capsules) — organs  which  from  the 
constancy  of  their  characters  have  long  been  re- 
cognised as  the  most  useful  basis  for  classification — 
Matonia  exhibits  distinctive  features. 

In  order  to  emphasise  the  isolated  position  of  the 


88  LINKS   WITH   THE   PAST  [ch. 

genus  it  has  recently  been  placed  in  a  separate 
family,  the  Matonineae,  of  which  it  is  the  sole  living 
representative.  The  restricted  geographical  range  of 
Matonia,  considered  in  connexion  witli  the  clearly 
marked  peculiarities  in  structure  and  form,  leads  us 
to  expect  other  evidence  in  support  of  the  natural 
inference  that  the  genus  is  a  survivor  of  a  once 
more  vigorous  and  widely  spread  family.  If  Matonia 
were  a  recently  evolved  type  which  has  not  spread 
far  from  its  original  home,  we  should  expect  it  to 
conform  more  closely  than  it  does  to  other  ferns  in 
the  Malay  region.  Even  assuming  for  the  sake  of 
argument  that  variation  may  occur  per  saltnm,  and 
new  forms  may  be  produced  differing  in  more  than 
the  finer  shades  of  small  variation  from  their  parents, 
the  peculiar  features  of  Matonia  are  too  pronounced 
and  its  individual  characteristics  too  obvious  to 
warrant  the  assumption  of  recent  production.  It  is, 
hoAvever,  from  the  testimony  of  the  rocks  that  we 
obtain  confirmation  of  the  opinion  that  these  Malayan 
species  are  plants  on  the  verge  of  extinction.  In 
shales  of  Jurassic  age  exposed  on  the  Yorkshire  coast 
at  Gristhorpe  Bay  and  in  iron-stained  rocks  of  the 
same  age  between  Whitby  and  Scarborough,  well 
preserved  leaves  have  been  found  agreeing  in  the 
shape  of  the  fi-ond,  as  also  in  the  form  of  the  leaflets 
and  of  the  groups  of  sporangia  which  they  bare,  with 
those  of  Matonia  pectinata. 


v]  FERNS  89 

The  exposure  by  a  stroke  of  the  hammer,  on  the 
fractured  surface  of  a  rock  picked  up  on  the  beach 
at  Hayburn  Wyke  (a  few  miles  south  of  Whitby),  of 
a  piece  of  fern  frond  which  is  unmistakably  closely 
allied  to  the  species  described  by  Wallace  on  Mount 
Ophir,  establishes  a  link  between  the  Jurassic  and 
the  present  era  and  presents  a  fascinating  problem  in 
geogi^aphical  distribution.  These  fossil  Matonias  are 
known  to  students  of  ancient  plants  as  species  of 
the  genus  Matonidium,  a  name  adopted  by  a  German 
botanist  for  specimens  apparently  identical  with  those 
from  the  Yorkshire  coast  discovered  in  slightly  younger 
rocks  (Wealden)  in  North  Germany.  The  same  type 
has  been  found  also  in  sediments  of  Wealden  age  on 
the  Sussex  coast.  Other  leaf-impressions  agreeing 
closely  with  those  of  Matonidium  have  been  obtained 
from  the  Yorkshire  Jurassic  rocks  and  these  are 
assigned  to  another  genus  Laccopteris,  an  extinct 
member  of  the  family  Matonineae.  It  is  not  merely 
in  the  habit  of  the  fronds  and  in  the  shape  and 
venation  of  the  leaflets  that  these  fossil  ferns  resemble 
the  existing  species,  but  the  more  important  features 
exhibited  by  the  spore-capsules  supply  additional  evi- 
dence. It  has  already  been  pointed  out  that  the  stems 
of  Matonia  are  characterised  by  a  type  of  structure 
unknown  in  an  identical  form  in  any  other  recent  fern. 

A  few  years  ago  Prof.  Bommer  discovered  frag- 
ments of  leaves  and  stems  in  Wealden  beds  a  few 


90  LINKS   WITH   THE   PAST  [ch. 

miles  from  Brussels  sufficiently  well  preserved  to 
reveal  the  details  of  internal  organisation.  Some 
of  these  fossils  were  found  to  possess  structural 
features  identical  Avith  those  of  the  Malayan  species 
of  Matonia.  A  full  account  of  the  fossil  representa- 
tives of  the  Matonia  family  would  be  out  of  place  in 
a  general  essay  on  Links  with  the  Past,  but  brief 
reference  may  be  made  to  some  of  the  data  which 
throw  light  on  the  geological  history  of  the  family. 
In  strata  classed  by  geologists  as  Rhaetic,  a  phase 
of  earth-history  between  the  Triassic  and  Jurassic 
eras  (see  p.  42),  species  of  Laccopteris  and  allied  forms 
have  been  described  from  several  otlier  countries  ; 
from  Jurassic  and  Wealden  strata  examples  of  both 
Laccopteris  and  Matonia  have  been  found  in  Germany, 
Portugal,  Belgium,  Austria,  and  elsewhere.  From 
rocks  of  Cretaceous  age,  higher  in  the  series  than 
the  Wealden  strata,  Avell  preserved  impressions  of 
a  Matonidium  have  been  discovered  in  JMoravia. 
The  Matonineae  were  widely  distributed  in  Europe 
during  the  Rhaetic  and  Jurassic  periods,  but,  so  far 
as  we  know,  the  family  did  not  survive  in  the  northern 
hemisphere  beyond  the  limits  of  the  Cretaceous 
period.  It  is  noteworthy  that,  in  spite  of  the 
preservation  of  the  remains  of  Jurassic  and  Cre- 
taceous floras  in  many  extra-European  regions, 
notably  in  India,  South  Africa,  Australia,  China,  and 
Tonkin,  no  specimens  have  been  found  which  can 


V]  FERNS  91 

with  confidence  be  assigned  to  the  Matonineae.  A 
single  fossil  has,  however,  been  described  from  Queens- 
land which  may  be  a  piece  of  a  Laccopteris  frond. 

There  is  some  evidence  that  ferns  very  similar  to 
INIatonia  existed  in  North  America  during  the  Meso- 
zoic  period.  It  would  be  in  the  highest  degree  rash 
to  assume  that  the  Matonineae  played  no  part  in 
the  Jurassic  vegetation  of  India,  South  Africa,  and 
other  southern  lands,  but  there  can  be  little  doubt 
that  the  family  was  especially  characteristic  of 
European  floras  during  a  portion  of  the  Mesozoic 
era.  It  would  seem  that  subsequent  to  the  Wealden 
period  the  ancestors  of  Matonia  dwindled  in  numbers 
and  their  geographical  range  became  much  more 
restricted. 

The  records  of  Tertiary  rocks  have  hitherto  added 
nothing  to  our  knowledge  of  the  distribution  of  the 
family  subse(pient  to  the  Cretaceous  period.  All 
we  can  say  is  that  the  existing  species  of  INIatonia 
are  the  last  survivoi's  of  a  family  which  in  the 
Jurassic  period  overspread  a  wide  area  in  Europe 
and  probably  extended  to  the  other  side  of  the 
Atlantic.  Exposed  to  unfavourable  climatic  con- 
ditions and  possibly  affected  by  the  revolution  in 
the  plant  world  consequent  on  the  appearance  of 
the  Flowering  Plants,  the  Matonineae  gradually 
retreated  beyond  the  equator  until  the  two  surviving 
species  found  a  last  retreat  in  the  Malayan  region. 


92 


LINKS   WITH   THE   PAST  [ch. 


P'ig.  12.  Dipteris  conjugata  Kein.  anJ,  in  the  middle  of  the  upper 
part  of  the  photograph,  a  frond  of  Matonia  pectinata  R.  Brown. 
Mount  Ophir.     (Pliotograph  by  Mr  A.  G.  Tansley.) 


V]  FERNS  93 

The  fern  spoken  of  by  Dr  Wallace  as  Dipteris 
Horsfieldii  (perhaps  better  known  as  DijJteris 
conjugata  (Fig.  12)),  which  grows  with  Matonia 
jjecthiata  on  Mount  Ophir  and  in  the  Malay  region 
generally,  is  one  of  seven  species  of  a  genus  charac- 
terised by  a  somewhat  wider  geographical  range 
than  Matonia.  Dipteris  conjugata  extends  to  the 
Philippines,  Samoa,  Fiji,  New  Caledonia,  New  Guinea 
and  Central  China  ;  its  fronds,  like  those  of  Matonia, 
are  borne  on  long  slender  stalks  attached  to  a 
creeping  stem  ;  they  have  a  broad  lamina  divided  by 
a  deep  median  sinus  into  two  symmetrical  halves  and 
each  half  is  cut  up  into  segments  with  a  saw-like 
edge.  Several  stout  ribs  spread  through  the  lamina 
from  the  apex  of  the  long  stalk  like  the  open  fingers 
of  a  hand  ;  from  these  ribs  smaller  veins  are  given 
off  at  a  wide  angle,  and  these  in  turn  give  rise  to  a 
reticulum  of  finer  veins  forming  a  skeletal  system 
like  that  in  the  leaves  of  an  oak  and  many  other 
flowering  plants. 

Numerous  groups  of  spore-capsules  are  borne  on 
the  lower  surface  of  the  broad  lobed  frond.  The 
leaves  of  other  species  of  Dipteris  have  the  same 
type  of  structure,  but  in  some  the  segmentation  of 
the  lamina  is  carried  further  and  the  leaf  consists  of 
numerous  long  and  narrow  segments  with  one  or  two 
main  ribs.  Dipteris  is  represented  in  the  flora 
of  Assam,  and  it  is  interesting  to  find  that  a  species 


94  LINKS   WITH   THE   PAST  [ch.  v 

recently  discovered  in  Borneo  is  more  closely  con- 
nected witli  the  Assam  type  than  with  those  of  the 
IMalay  region.  Until  a  few  years  ago  the  genus 
Dipteris  was  included  in  the  large  family  Polypodi- 
aceae  of  which  nearly  all  our  British  ferns  are 
members,  but  the  discovery  of  certain  distinguishing 
features  in  the  structure  of  the  sporangia  showed 
that  these  Eastern  and  Southern  species  form  a 
fairly  well-defined  group  worthy  of  family  rank. 

In  the  Rhaetic  plant-beds  of  Northern  and 
Central  Europe,  of  North  America,  Tonkin,  and 
elsewhere,  numerous  fossil  leaves  have  been  dis- 
covered which  in  shape,  venation,  and  in  the 
manner  of  occurrence  of  the  sporangia  bear  a  close 
resemblance  to  species  of  Dipteris.  Ferns  of  this 
type  were  abundant  in  the  Jurassic  floras  of  the 
northern  hemisphere,  and  it  is  interesting  to  find 
impressions  of  Dipteris-like  leaves  both  in  the 
Jurassic  rocks  of  the  Yorkshire  coast  as  well  as  in 
slightly  newer  beds  of  the  same  geological  period  on 
the  north-east  coast  of  Sutherland. 

It  is  impossible  to  say  with  confidence  how  nearly 
these  Rhaetic  and  Jurassic  ferns  were  related  to  the 
existing  species,  as  our  knowledge  of  them  is  less 
complete  than  in  the  case  of  the  fossil  representatives 
of  the  Matonineae,  but  there  can  be  no  reasonable 
doubt  that  in  Dipteris  as  in  Matonia  we  have  a  con- 
necting link  between  the  present  and  a  remote  past. 


CHAPTER  VI 

THE   REDWOOD   AND   MAMMOTH   TREES 
OF   CALIFORNIA 

'Your  sense  is  sealed,  or  you  should  hear  them  tell 
The  tale  of  their  dim  life,  with  all 
Its  compost  of  experience '     W.  E.  Henley. 

Since  their  introduction  into  England  about  the 
middle  of  the  nineteenth  century,  the  two  Californian 
species  Sequoia  sempervirens  (the  Redwood)  and 
Sequoia  gigantea  (the  Mammoth  tree)  have  become 
familiar  as  cultivated  trees.  The  name  Sequoia, 
said  to  be  taken  from  Sequoiah,  the  inventor  of  the 
Cherokee  alphabet,  was  instituted  in  1847,  while  the 
name  Wellingtonia,  often  used  in  horticulture  though 
discarded  by  botanists  in  favour  of  the  older  designa- 
tion Sequoia,  was  proposed  in  1853.  Both  species 
are  now  confined  to  a  comparatively  small  area  in 
California  :  their  restricted  geographical  range,  con- 
sidered as  an  isolated  fact,  might  be  regarded  as  a 
sign  of  recent  origin.  The  records  of  the  rocks, 
however,  afford  ample  proof  that  rarity  in  this  as  in 


96  LINKS  WITH   THE   PAST         [ch.  vi 

many  other  instances  is  the  precursor  of  extinction. 
The  famous  groves  of  Mariposa  and  Calaveras 
represent  the  last  resting-place  of  giant  survivors 
of  a  race  Avhich  formerly  held  its  own  in  Europe  and 
in  other  parts  of  the  world. 

The  Redwood,  Sequoia  sempervirens,  occupies  a 
narrow  belt  of  country,  rarely  more  than  20  or  30 
miles  from  the  coast,  three  hundred  miles  long  from 
Monterey  in  the  south  to  the  frontiers  of  Oregon  ; 
it  has  a  stronger  hold  on  existence  than  Sequoia 
gigantea.  In  Northern  California  it  still  forms  pure 
forests  on  the  sides  of  ravines  and  on  the  banks  of 
streams.  The  tapering  trunk,  rising  from  a  broad 
base  to  over  300  ft.,  gives  off  short  horizontal 
branches  thickly  set  with  narrow  spirally  disposed 
leaves  i — J  inch  in  length  arranged  in  two  ranks 
like  the  similar  leaves  of  the  Yew.  The  lower 
edge  of  each  leaf  is  decurrent,  that  is  it  runs  a 
short  distance  doAvn  the  axis  of  the  branch  instead  of 
terminating  at  the  point  of  attachment.  It  is  by 
paying  attention  to  such  details  as  this  as  well  as  to 
more  important  features,  that  we  are  able  to  connect 
fragmentary  fossil  twigs  with  those  of  existing 
species.  The  female  'flowers'  have  the  form  of 
oblong  cones  from  |  to  1  inch  long  :  each  consists 
of  a  central  axis  bearing  crowded  wedge-shaped, 
woody  appendages  or  cone-scales,  which  gradually 
increase  in  breadth  towards  the  exposed  distal  end 


Fig.  13,     Sequoia  gigantea.     King's  Co.,  California. 
(From  Prof.  D.  H.  Campbell) 


98  LINKS   WITH   THE   PAST         [ch.  vi 

characterised  b}'  its  four  sloping  sides  and  by  a 
median  transverse  groove.  Several  small  seeds  are 
borne  on  the  upper  surface  of  the  cone-scales.  The 
smaller  and  short-lived  male  flowers  need  not  be 
described. 

The  other  and  better  known  species  Sequoia 
glgatitea  (Fig.  13)  has  an  even  more  restricted  range 
and  is  confined  to  groves  on  the  western  slopes  of 
the  Sierra  Nevada  between  3000  to  9000  ft.  above 
sea-level. 

This  tree  is  at  once  distinguished  from  the 
Redwood  by  its  ovate,  sharply  pointed  and  stiffer 
leaves  which  retain  their  spiral  disposition  and 
closely  surround  the  axis  of  the  twigs  like  obliquely- 
set  needles.  The  cones  are  of  the  same  type  as  those 
of  Sequoia  sempervirens,  but  are  broader  and  may 
attain  a  length  of  3^  inches  (9*5  cm.)  (Fig.  14). 

Reference  has  already  been  made  to  Sequoia 
as  a  striking  illustration  of  longevity.  It  is  also 
selected  as  an  equally  impressive  example  of  a  tjpe 
verging  on  extinction,  which  played  a  prominent  part 
in  the  vegetation  of  both  west  and  east  during  the 
Cretaceous  and  Tertiary  periods. 

Scraps  of  branches  with  leaves  hardly  distinguish- 
able from  those  of  the  existing  Californian  trees 
are  frequently  met  with  in  Tertiary  and  Mesozoic 
sediments,  and  with  them  occasionally  occur  cones 
too    imperfectly    preserved    to    aftbrd    satisfactory 


Fig.   14.     Sequoia  gigantea  Torr.     (|  nat.  size.) 


7—2 


100  LINKS   WITH   THE  PAST  [ch. 

evidence  of  more  tlian  superficial  agreement  with 
those  of  tlic  recent  species.  The  task  of  deciphering 
the  past  history  of  plants,  particularly  of  the  Conifers, 
is  accompanied  by  many  difficulties  and  insidious 
temptations.  It  is  clear  from  a  critical  examination 
of  many  of  the  recorded  instances  of  fossil  Sequoias 
that  the  generic  name  has  been  frequently  used  by 
writers  without  adequate  grounds.  The  fragmentary 
specimens  available  to  the  botanical  historian  cannot 
as  a  rule  be  subjected  to  microscopical  investigation, 
and  even  a  partial  acquaintance  with  the  similarity 
of  the  foliage  of  different  types  of  living  Conifers  is 
sufficient  to  convince  the  student  of  the  need  of  self- 
control  in  the  identification  of  the  fossils.  It  is, 
how^ever,  easy  to  point  out  obvious  pitfalls,  though 
difficult  to  maintain  a  judicial  attitude  in  the 
excitement  of  endeavouring  to  interpret  documents 
which  are  too  inconq^lete  to  be  identified  with 
certainty.  If  w^e  put  on  one  side  all  records  of 
supposed  fossil  Sequoias  not  based  on  satisfactory 
data,  there  remains  a  wealth  of  material  testifying  to 
the  antiquity  of  the  surviving  species. 

It  is  by  no  means  improbable  that  Conifers 
closely  allied  to  the  RedAvoods  and  Mammoth  trees 
of  California  were  represented  in  Jurassic  floras  ; 
but  hitherto  no  proof  has  been  obtained  of  the 
occurrence  of  a  Sequoia  among  the  rich  material 
aflbrded  by   the  Jurassic  plant-beds  of   Yorkshire 


VI]      REDWOOD  AND  MAMMOTH  TREES      101 

and  by  beds  of  tlie  same  age  in  other  countries. 
A  small  cone  has  recently  been  described  from 
strata  near  Boulogne  belonging  to  the  latest  phase 
of  the  Jurassic  period,  which  presents  a  strong 
resemblance  in  shape  and  size  and  in  the  form  of  the 
cone-scales  to  those  of  the  recent  species.  This  speci- 
men, though  not  conclusive,  is  the  most  satisfactory 
indication  of  a  Jurassic  Sequoia  so  far  discovered. 
From  Lower  Jurassic  rocks  in  Madagascar  similar 
cones  have  been  recorded  in  association  with  foliage- 
shoots  like  those  of  Sequoia  gigantea,  but  here  too 
the  evidence  is  not  beyond  suspicion.  In  plant- 
bearing  strata  of  Wealden  age,  such  as  are  exposed 
in  the  cliff  near  Hastings  and  in  deposits  of  the  same 
age  in  North  Germany,  Portugal,  and  elsewhere, 
twigs  and  cones  have  been  found  Avhich  may  be 
those  of  trees  nearly  allied  to  the  genus  Sequoia. 

It  is,  however,  in  the  sedimentary  rocks  of 
Cretaceous  age,  rather  higher  in  the  series  than 
those  in  the  Hastings  cliffs,  and  in  the  succeeding 
Tertiary  rocks,  that  undoubted  Sequoias  are  met 
with  in  abundance.  At  Bovey  Tracey  in  Devonshire 
there  is  a  basin-shaped  depression  in  the  granitic  rocks 
of  Dartmoor  filled  with  clay,  gravel  and  sand — the 
flood-deposits  of  a  Tertiary  lake  containing  waifs  and 
strays  of  the  vegetation  on  the  surrounding  hills. 
Among  the  commonest  plants  is  one  to  which  the 
late  Oswald  Heer  gave  the  name  Sequoia  CouUsiae, 


102  LINKS   WITH  THE  PAST  [cH. 

and  his  reference  of  the  specimens  to  the  genus 
Sequoia  has  been  confirmed  by  the  recent  researches 
of  Air  and  Mrs  Clement  Reid(5o).  This  Tertiary 
(Oligocene)  species  is  represented  by  slender  twigs 
almost  identical  with  those  of  Sequoia  glgantea  and 
by  well-preserved  cone-scales  and  seeds  (Fig.   15). 


i» 


A  B 

Fig.  15.  Sequoia  Couttsiae  Heer.  Twigs  (A)  and  cone-scales  (B) 
from  Bovey  Tracey.  (  x  3. )  (Photographs  by  Mr  and  Mrs  Clement 
Beid.) 

Moreover,  it  has  been  possible  to  examine  micro- 
scopically the  structure  of  the  carbonised  outer  skin 
of  the  leaves  and  to  demonstrate  its  agreement  with 
that  of  the  superficial  tissue  in  the  leaves  of  the 
Mammoth   tree.     With   the   Bovey   Tracey   Sequoia 


VI]      REDWOOD  AND  MAMMOTH  TREES      103 

are  associated  fragments  of  Magnolia,  Vitis,  and 
Taxodium  dlstichum,  the  swamp  Cypress  of  North 
America,  together  with  other  types  which  have  long 
ceased  to  exist  in  Western  Europe.  Other  British 
examples  of  Sequoia  have  been  described  from 
Tertiary  beds  at  Bournemouth,  the  Isle  of  Wight, 
Sheppey,  and  Antrim,  but  the  material  from  these 
localities  is  inferior  in  preservation  and  cannot  be 
identified  with  the  same  degree  of  certainty  as  in  the 
case  of  the  Devonshire  specimens.  The  occurrence 
of  twigs  and  cones  of  several  species  of  Sequoia  in 
both  Cretaceous  and  Tertiary  rocks  in  Austria, 
Germany,  Italy,  France,  and  elsewhere,  shows  that 
the  ancestors  of  the  Californian  trees  were  common 
in  the  European  region. 

The  exploration  of  Cretaceous  and  Tertiary  rocks 
in  Arctic  Europe  has  revealed  the  former  existence  in 
Greenland,  Spitzbergen,  and  other  more  or  less  ice- 
covered  lands  of  plants  which  clearly  denote  a  mild 
climate.  Cones  and  branches  of  Sequoias  have  been 
found  in  abundance  in  Lower  Tertiary  beds  on  Disco 
Island  off  the  west  coast  of  Greenland,  and  similar 
evidence  of  the  northern  extension  of  the  genus  has 
been  obtained  from  Spitzbergen.  DrNathorst  of  Stock- 
holm speaks  of  twigs  of  Sequoia  in  the  Tertiary  clays 
of  Ellesmere  Land  almost  as  perfect  as  herbarium 
specimens.  In  Tertiary  beds  on  the  banks  of  the 
Mackenzie  River,  in   Alaska,  Saghalien   Island  and 


104  LINKS  WITH  THE  PAST  [ch. 

Vancouver  Island,  and  in  Upper  Cretaceous  rocks  in 
the  Queen  Charlotte  Islands,  remains  of  Sequoia  have 
been  discovered.  One  of  the  most  remarkable  in- 
stances of  the  preservation  of  trees  of  a  bygone  age 
is  supplied  by  the  volcanic  deposits  of  Lower  Tertiary 
age  exposed  on  the  slopes  of  Amethyst  mountain 
in  the  Yellowstone  Park  district.  At  different  levels 
in  the  volcanic  and  sedimentary  material,  which  is 
piled  up  to  a  height  of  over  2000  ft.  above  the  valley, 
as  many  as  fifteen  forests  are  represented  by  erect 
and  prostrate  limbs  of  petrified  trees  (Fig.  G).  The 
microscopical  examination  of  some  of  these  trees 
has  shown  that  they  bear  a  striking  resemblance  to 
Sequoia  semiiervirens.  In  a  photograph  of  these 
petrified  forests  by  the  U.S.  Geological  Survey  (36,2) 
one  sees  living  Conifers  side  by  side  with  the  lichen- 
covered  and  weathered  trunks  of  the  fossil  species 
{Sequoia  tnagiufica),  living  and  extinct  being  at  a 
distance  hardly  distinguishable.     (Frontispiece.) 

In  concluding  this  brief  survey  of  the  fossil  records 
of  Sequoia,  reference  may  be  made  to  the  discovery 
of  petrified  wood  in  Cretaceous  rocks  in  South  Nevada, 
possessing  the  anatomical  featnresof  Sequoia (/igantea, 
which  shows  that  close  to  the  present  home  of  the  big 
trees  their  ancestors  flourished  during  a  period  of  the 
earth's  history  too  remote  to  be  measured  by  human 
reckoning. 

The  distribution  of  the  Tertiary  and  Cretaceous 


VI]     REDWOOD  AND  MAMMOTH  TREES     105 

Sequoias  would  appear  to  have  been  mainly  in  the 
northern  hemisphere,  extending  well  within  the  Arctic 
circle.  It  is,  however,  by  no  means  improbable  that 
the  ancestors  of  Sequoia  flourished  far  south  of  the 
equator.  Reference  has  been  made  to  Jurassic  fossils 
from  Madagascar  which  have  been  compared  with  the 
existing  species,  and  from  LoAver  Tertiary  beds  in 
New  Zealand  the  late  Baron  Ettingshausen  described 
some  cones  and  twigs  as  Sequoia  novae  zeelandicae 
which  bear  a  close  resemblance  to  the  existing  type. 
The  available  evidence  would  seem  to  point  to  a 
northern  origin  of  the  genus,  though  allowance  must 
be  made  for  erroneous  conclusions  based  on  negative 
evidence.  Further  research  may  well  extend  the  past 
distribution  of  Sequoia  in  southern  lands,  but  the 
data  to  hand  point  to  the  conclusion  that  the  Cali- 
fornian  trees  represent  the  survivors  of  a  type  which 
flourished  in  the  Cretaceous  and  Tertiary  periods 
over  a  wide  area  in  North  America  and  in  what  we 
now  call  the  Continent  of  Europe. 


CHAPTEll  VII 

THE   ARAUCARIA  FAMILY 

'And  so  the  grandeur  of  the  Forest-tree 
Comes  not  by  casting  in  a  formal  mould, 
But  from  its  own  divine  vitality.'     Wordsworth, 

As  an  additional  illustration  of  existing  cone- 
bearing  trees  which  form  links  with  the  past  we  may 
briefly  consider  the  genera  Araucaria  and  Agathis, 
the  two  members  of  the  family  Araucarieae.  It  is 
generally  agreed  that  the  branches  of  the  genealogical 
tree  of  this  family  extended  farther  back  into  the 
past  than  in  the  case  of  the  majority  of  Conifers.  By 
some  authors  the  surviving  representatives  of  the 
x\raucarian  stock  are  considered  to  have  a  strong 
claim  to  be  regarded  as  the  most  primitive  as  well  as 
the  oldest  of  cone-bearing  trees,  though  this  opinion, 
like  many  others,  is  not  held  by  botanists  as  a  whole. 
This  is  not  the  place  to  discuss  matters  of  controversy, 
and  I  shall  confine  myself  to  a  general  consideration 
of  Araucaria  and  Agathis  from  the  point  of  view  of 
their  present  distribution  and  the  part  they  played  in 


CH.  VII]     THE  ARAUCARIA  FAMILY  107 

the  vegetation  of  the  Mesozoic  and  Tertiary  epochs. 
In  1741  a  plant  from  Amboyna,  one  of  the  Moluccas,  was 
described  under  the  name  Dammara  alba.  For  this 
tree,  known  as  the  Amboyna  Fine,  the  English  botanist 
Salisbury  instituted  the  generic  name  Agathis,  from  a 
Greek  word  (dyadic)  meaning  a  ball  of  string  and  pro- 
bably suggested  by  the  form  of  the  cones,  which  is  the 
designation  usually  adopted  in  botanical  literature 
instead  of  the  pre-Linnean  term  Dammara.  The  best 
known  species  of  the  genus  is  the  Kauri  Pine,  probably 
the  finest  forest  tree  in  New  Zealand  where  it  still 
flourishes  from  the  North  Cape  to  latitude  38°  S., 
though  the  occurrence  of  sub-fossil  trunks  and  pieces 
of  buried  resin  shows  that  the  Kauri  forests  are  gradu- 
ally dwindling.  The  stems  of  this  species,  Agathis 
australis,  rise  like  massive  grey  columns  to  a  height 
of  160  ft.,  terminating  in  a  succession  of  spreading 
branches  given  off*  in  tiers  from  the  main  trunk.  The 
thick  narrow  lanceolate  leaves,  with  several  parallel 
veins,  reach  a  length  of  2  to  3  inches.  The  female 
shoots  have  the  form  of  small  and  almost  spherical 
cones  consisting  of  a  central  axis  bearing  overlapping 
spiral  series  of  broadly  triangular  scales  (Fig.  16). 
Each  scale  carries  a  single  seed  with  a  large  wing 
attached  to  one  side  which  facilitates  disposal  by 
wind.  Other  species  of  Agathis  occur  in  the  Malay 
Archipelago,  the  Philippines,  in  Queensland,  in  the 
New  Hebrides,  New  Caledonia,  the  Fiji  Islands,  and 


108  LINKS  WITH  THE  PAST  [ch. 


VII]  THE  ARAUCARIA  FAMILY  109 

elsewhere.  With  the  exception  of  the  Australian 
Kauri  (Agathis  rohusta),  with  leaves  larger  and 
broader  than  those  of  the  New  Zealand  Kauri,  the 
genus  is  essentially  an  island  type.  With  the  ex- 
ception of  some  species  of  the  southern  hemisphere 
genus  Podocarpus,  there  are  no  Conifers  with  foliage 
like  that  of  Agathis.  It  is,  however,  the  broad  and  thin 
single-seeded  scales  and  the  spherical  cones,  in  some 
species  six  inches  in  length,  which  furnish  the  most 
trustworthy  means  of  identifying  the  genus. 

The  allied  genus  Araucaria,  with  the  exception 
of  two  South  American  species,  the  familiar  Monkey 
Puzzle,  Araucaria  imbricata,  and  a  Brazilian  tree, 
Araucaria  hrasiliana,  is  confined  within  the  geo- 
graphical area  occupied  by  Agathis.  The  name  Arau- 
caria was  first  used  by  de  Jussieu  in  1789  for  a  plant 
previously  referred  to  the  genus  Pinus  and  described 
as  one  of  the  most  beautiful  trees  of  Chili.  This 
species,  A.  imbricata,  introduced  into  England  in 
1796,  grows  on  the  southern  slopes  of  the  Andes  and, 
as  in  the  case  of  the  Kauri  forests  of  New  Zealand, 
buried  stems  point  to  a  wider  extension  of  the  forests 
in  earlier  days.  The  sharp  and  thick  leaves  of  the 
Monkey  Puzzle  distinguish  it  from  all  other  Conifers  ; 
its  large  almost  spherical  seed-bearing  cones,  more 
than  half  a  foot  in  length,  which  may  occasionally  be 
seen  on  well-grown  British  trees,  are  unlike  those  of 
other  genera.     Each  of  the  deep  and  narrow  scales 


110 


LINKS  WITH   THE    PAST 


[CH. 


bears  a  single  seed  embedded  in  the  substance  of  the 
scale  and  terminates  distally  in  a  narrow  upturned 
process.  Some  species  of  Araucaria,  differing  con- 
siderably in  the  form  of  the  leaves  and  in  the  shape 
and  structure  of  the  seed-scales  from  the  Chilian 
species,  are  conveniently   placed  in  a  distinct  sub- 


Fig.  17.     Araucaria  excelsa.     The  upper  part  of  a  small  tree  in  the 
Cambridge  Botanic  Garden.     (Much  reduced.) 


division  of  the  genus  Araucaria.  Of  this  type  the 
Norfolk  Island  Pine,  Araucaria  cxcelsa,  is  the  best- 
known  example  (Fig.  17).  It  was  introduced  to  Kew 
by  Sir  Joseph  Banks  in  1/93,  soon  after  its  discovery 
by   Captain   Cook,  who  describes  the  stems   of  the 


VII]  THE   ARAUCARIA   FAMILY  111 

Norfolk  Island  trees  as  resembling  basaltic  columns, 
and  relates  how  on  approaching  the  island  everyone 
was  satisfied  that  the  columnar  objects  were  trees, 
*  except  our  Philosophers,  who  still  maintained  they 
were  basaltes.'  The  leaves  are  short,  about  half  an 
inch  long,  laterally  compressed  and  slightly  spreading 
and  sickle-shaped — sometimes  shorter  and  broader 
and  overlapping — arranged  in  crowded  spirals.  The 
scales  of  the  broadly  oval  cones  are  single-seeded,  but 
differ  from  those  of  Arancaria  imhricata  in  having  the 
seed  exposed  on  the  surface  and  in  the  greater  breadth 
and  thinner  borders  of  the  scales.  In  both  Araucaria 
and  Agathis  the  nature  of  the  seed-scales  constitutes 
a  distinguishing  feature.  The  leaves  of  Arcmcarla 
imhricata  differ  in  form  from  those  of  other  Conifers. 
The  foliage  shoots  of  Araucaria  excclsa  and  other 
species,  e.g.  the  very  closely  allied  A.  Cooldi  of  the 
New  Hebrides  and  New  Caledonia,  though  not  unlike 
the  branches  of  a  Japanese  Conifer  {Cryptomeria 
japouica),  often  cultivated  in  England,  afford  fairly 
trustworthy  characters  for  identification  purposes. 

The  minute  structure  of  the  wood  of  both  Araucaria 
and  Agathis  constitutes  an  important  distinguishing 
feature  and  enables  us  to  recognise  on  microscopical 
examination  even  a  fragment  of  wood  of  either  of 
these  genera.  The  small  elongated  cells  or  water- 
conducting  elements  of  the  wood  of  the  Araucarieae 
are  characterised  by  one  or  two,  and  occasionally  as 


112  LINKS   WITH   THE   PAST  [ch. 

many  as  three  or  four,  contiguous  rows  of  pits  on  their 
radial  walls,  and  these  appear  in  surface  view  as 
flattened  circles  or  polygonal  areas. 

These  details  have  been  mentioned  in  order  to  show 
that  Araucaria  and  Agathis  are  sufficiently  distinct 
in  many  respects  from  other  Conifers  to  render  their 
identification  in  a  fossil  state  comparatively  easy,  at 
least  much  easier  than  the  recognition  of  the  majority 
of  the  members  of  the  Coniferae.  It  would  be  going 
too  far  to  state  definitely  that  Araucarieae,  as  defined 
by  reference  to  existing  species,  existed  during  the 
Palaeozoic  period  ;  on  the  other  hand  it  would  seem 
in  a  high  degree  probable  that  the  vegetation  of  the 
Coal  age  and  of  the  succeeding  Permian  period  in- 
cluded trees  in  which  certain  Araucarian  characters 
were  clearly  foreshadowed.  The  name  Araucarioxylon 
was  formerly  applied  to  petrified  wood,  obtained  from 
Palaeozoic  as  well  as  from  later  formations,  which 
agrees  anatomically  with  that  of  Araucaria  and  Agathis. 
It  has  been  shown  in  recent  years  that  much  of  the 
Palaeozoic  wood  of  this  type  of  structure  belongs 
to  the  extinct  genus  Cordaites,  a  tree  which  played 
a  prominent  part  in  the  earlier  floras.  Cordaites 
affords  a  good  example  of  a  generalised  type  :  in 
its  wood-structure  it  resembles  very  closely  the 
existing  Araucarieae  ;  its  long  strap-like  leaves  are 
not  unlike  those  of  some  species  of  Agathis ;  its 
male  flowers  have  often  been  compared  with  those 


VII]  THE   ARAUCARIA  FAMILY  113 

of  the  Maiden  Hair  tree,  Ginlcgo  hiloha,  and  certain 
anatomical  features  form  connecting  links  between 
this  Palaeozoic  genus  and  the  Cycads. 

It  is  noteworthy  that  in  another  Palaeozoic  genus, 
Walchia,  the  leaf-bearing  branches  are  identical  in  ap- 
pearance with  those  of  the  Norfolk  Island  Pine  (Fig.  17) 
and  some  other  species  of  Araucaria.  Unfortunately 
our  knowledge  of  the  reproductive  organs  of  Walchia 
is  insufficient  to  warrant  any  definite  statement  as  to 
the  degree  of  consanguinity  between  this  Permian  and 
Upper  Carboniferous  plant  and  the  Araucarieae  ;  it 
is  probable  that  in  Walchia  we  have  a  type  not  far 
removed  from  the  line  of  evolution  which  led  to 
Araucaria.  Petrified  wood,  identified  as  that  of 
Walchia,  and  exhibiting  the  Araucarian  type  of  struc- 
ture, has  been  recorded  from  Permian  rocks  of  the 
Vosges.  Other  instances  might  be  quoted  in  support 
of  the  view  that  the  Palaeozoic  floras  included  a  few 
plants  with  which  the  surviving  Araucarieae  may 
fairly  claim  relationship.  Professor  Zeiller  of  Paris 
has  recently  described  some  fossil  shoots  from  Palaeo- 
zoic rocks  in  India  under  the  name  xiraucarUcs 
Oldhami  on  the  ground  of  the  similarity  of  the  leaves 
to  those  of  Araucaria  imhricata.  Similarly,  from 
Triassic  rocks  several  fossils  have  been  described  as 
closely  allied  to  Araucaria,  in  some  cases  because  of 
anatomical  resemblances  and  in  others  on  the  less 
satisfactory  evidence  furnished  by  a  similarity  in  the 
s.  8 


114  LINKS   WITH   THE   PAST  [ch. 

foliage  slioots.  Professor  Jeffrey  of  Harvard  has  re- 
cently given  an  account  of  a  new  type  of  stem 
(Woodworthia)  from  the  petrified  Triassic  forest  of 
Arizona  possessing  some  Araucarian  characters, 
though  differing  from  existing  species  of  Araucaria 
in  certain  structural  features,  a  combination  of 
characters  regarded  by  this  Author  as  an  indication 
of  relationship  with  the  family  of  Conifers,  which 
includes  the  Pines,  Firs,  Larches  and  other  well-known 
northern  genera. 

It  is,  however,  from  the  records  of  Jurassic  rocks 
that  we  obtain  the  most  satisfactory  information  as  to 
the  great  antiquity  and  the  very  wide  geographical 
range  of  the  ancestors  of  the  recent  genus.  The  plant- 
beds  of  the  Yorkshire  coast  afford  clear  evidence  of 
the  occurrence  of  Araucarian  trees  in  the  woodlands 
of  the  Jurassic  period.  Petrified  wood  has  been  found 
at  Whitby,  associated  with  jet,  showing  the  minute 
structural  characteristics  of  the  surviving  species  of 
Araucarieae,  and  it  is  not  improbable  that  some  at 
least  of  the  Whitby  jet  has  been  formed  from  the  wood 
of  Araucarian  plants.  The  carbonised  remains  of 
leafy  shoots  preserved  in  the  Jurassic  shales  near 
Scarborough  and  on  other  parts  of  the  Yorkshire 
coast  include  twigs  hardly  distinguishable  from  those 
of  Araucaria  excelsa,  though  the  resemblance  of 
external  form  alone,  especially  in  the  case  of  foliage 
shoots,  does  not  amount  to  proof  of  generic  identity. 


VII]  THE  AR  AUG  ARIA  FAMILY  115 

We  have,  however,  the  much  more  trustworthy  evi- 
dence of  cones  and  seed-bearing  scales  in  which  the 
characteristic  features  of  living  species  are  clearly 
shown.  Seed-bearing  scales  almost  identical  with  those 
of  Arancaria  excel sa  and  other  recent  species  have 
long  been  known  from  the  Jurassic  rocks  of  Yorkshire. 

From  other  parts  of  England  where  samples  of 
Jurassic  floras  are  preserved,  as  at  Stonesfield  in 
Oxfordshire,  in  Northamptonshire  and  elsewhere, 
equally  striking  examples  of  undoubted  Araucarias 
have  been  found. 

Fig.  18  represents  part  of  a  large  cone  described 
in  1866  by  Mr  Carruthers  from  Jurassic  rocks  at 
Bruton  in  Somersetshire  :  this  specimen,  now  in  the 
British  INIuseum,  consists  of  one  side  of  a  spherical 
cone  about  5  inches  long  and  5  inches  broad ;  in  size, 
as  in  the  form  of  the  seed-scales,  it  shows  a  striking 
likeness  to  the  cones  of  the  Australian  species 
Araucaina  BidwilliL  the  Bunya  Bunya  of  Queens- 
land. Other  equally  convincing  examples  of  Jurassic 
Araucarian  cones  and  seeds  may  be  seen  in  the 
museums  of  York  and  Northampton.  On  the  north- 
east coast  of  Sutherland  there  is  a  narrow  strip  of 
Jurassic  beds  forming  a  low  platform  between  the 
granitic  and  Old  Red  Sandstone  hills  and  the  sea. 
From  these  rocks  Hugh  Miller  described  several 
fossil  plants  in  his  Testimony  of  the  Bocls,  and  an 
examination  of  a  large  collection  obtained  from  this 

8—2 


116 


LINKS  WITH  THP]  PAST 


[CH. 


Fig.  18.     Araucarites  ^jylKwrocarpus  Carr.     From  Jurassic  rocks  at 
Bruton,  Somersetshire.     (British  Museum,     f  nat.  size.) 


VII]  THE  ARAUCARIA  FAMILY  117 

district  by  the  late  Dr  INIarciis  Guiin  shows  that 
Miller  was  justified  in  speaking  of  Araucaria  as  a 
member  of  this  northern  flora. 

There  is  abundant  evidence  pointing  to  the  exist- 
ence in  Britain  during  the  Jurassic  period,  and  in 
the  early  days  of  the  Cretaceous  epoch,  of  Araucarian 
trees  which  differed  but  slightly  from  the  modern 
species  confined  to  the  southern  hemisphere.  In 
several  localities  in  France,  Germany,  and  other  parts 
of  the  continent,  Araucarian  fossils  have  been  recog- 
nised in  Jurassic  rocks.  It  is  almost  certain  that 
some  foliage  shoots  and  imperfectly  preserved  cones 
described  by  Dr  Nathorst  from  Upper  Jurassic  rocks 
in  Spitzbergen  were  borne  by  a  species  of  Araucaria. 
Cone-scales  very  similar  to  those  from  Yorkshire  have 
been  discovered  in  Wealden  beds  in  Cape  Colony,  and 
Araucarian  wood  of  Jurassic  and  Cretaceous  age  has 
been  found  in  Madagascar.  From  Jurassic  strata  in 
India  and  Victoria  (Australia),  as  well  as  from  Upper 
Jurassic  and  Lower  Cretaceous  rocks  in  Virginia  and 
elsewhere  in  the  eastern  United  States,  Avell  preserved 
Araucarian  fossils  are  recorded.  In  a  collection  of 
Jurassic  plants,  obtained  a  few  years  ago  by  the 
members  of  a  Swedish  Antarctic  Expedition  in 
Graham's  Land,  Dr  Nathorst  has  recognised  some 
cone-scales  of  Araucaria,  which  demonstrate  a  former 
extension  of  the  family  beyond  the  southern  limits  of 
South  America. 


118  LINKS  WITH  THE   PAST  [ch. 

It  is  interesting  to  find  that  when  we  ascend  higher 
in  the  geological  series  and  pass  beyond  the  Wealden 
strata  to  the  Middle  and  Upper  sub-divisions  of  the 
Cretaceous  period,  evidence  of  the  Avide  geogra^jhical 
distribution  of  the  Araucarieae  is  still  abundant. 
Araucarian  wood  has  been  obtained  in  rocks  classed 
as  Upper  Cretaceous  in  Egypt,  in  East  Africa,  in 
Dakota,  and  elscAvhere.  In  the  sedimentary  rocks  of 
the  Tertiary  period  undoubted  examples  of  Araucaria 
are  less  common,  though  there  can  be  no  doubt  that 
the  genus  was  much  more  widely  spread  then  than 
it  is  at  the  present  day.  The  Avell-known  Tertiary 
plant-beds  of  Bournemouth  have  afforded  specimens 
of  foliage  shoots  which  have  been  described  as  a 
species  of  Araucaria,  though  in  the  absence  of  well- 
preserved  cones  or  petrified  Avood  we  must  admit 
that  the  data  are  inconclusive.  It  is,  however, 
legitimate  to  regard  the  striking  similarity  of  the 
Bournemouth  twigs  to  those  of  Araucaria  excelsa 
and  A .  CooJcii  as  constituting  a  fairly  strong  case  in 
favour  of  the  persistence  of  Araucaria  in  Western 
Europe  up  to  the  earlier  stage  of  the  Tertiary  period. 
Araucarian  wood  of  Tertiary  age  is  recorded  from 
India,  while  branches  with  broad  leaves  like  those 
of  Araucaria  imhricata  have  been  found  in  Seymour 
Island  and  the  ^lagellan  Straits,  and  specimens 
of  Tertiary  wood  are  described  from  Patagonia. 
At  the  other  end  of  the  world.  Tertiary  rocks  on  the 


VII]  THE   ARAUCARIA  FAMILY  119 

west  coast  of  Greenland  have  yielded  fragments  which 
may  be  referred  with  some  hesitation  to  the  genus 
Araucaria. 

A  few  words  must  be  added  in  regard  to  the  recent 
discovery  by  Professor  Jeffrey  and  Dr  Hollick  of  some 
very  interesting  Cretaceous  specimens  in  New  Jersey 
of  well-preserved  cone-scales  and  foliage  shoots  of 
extinct  plants  closely  related  to  the  existing  species 
of  Agathis  (51).  The  American  fossils  are  particularly 
valuable  because  their  preservation  admits  of  micro- 
scopical examination  of  the  tissues.  In  Cretaceous 
rocks  of  Staten  Island  and  in  other  localities  on  the 
eastern  border  of  the  northern  United  States,  kite- 
shaped  seed-bearing  scales  almost  identical  in  form 
with  those  of  recent  species  of  Agathis  are  fairly 
common  fossils.  Similar  specimens  have  long  been 
known  from  Tertiary  rocks  in  western  Greenland. 
In  the  case  of  some  of  the  American  examples  each 
scale  bore  three  seeds  instead  of  a  single  seed  in 
living  species:  on  account  of  this  difference  Prof. 
Jeffrey  and  Dr  Hollick  have  adopted  a  distinct 
generic  name,  Protodmnmara. 

The  foregoing  sketch  is  necessarily  far  from  com- 
plete, but  it  may  serve  as  aii  illustration  of  the  light 
which  is  thrown  on  the  past  history  of  recent  plants 
by  the  investigation  of  the  relics  of  ancient  floras. 
The  family  Araucarieae  now  represented  by  a  small 
number  of  species  which,  with  the  exception  of  the 


120  LINKS   WITH  THE   PAST        [ch.  vii 

Andian  and  Brazilian  Araucarias,  are  restricted  to  a 
small  region  in  the  southern  hemisphere,  was  one  of 
the  most  widely  spread  sections  of  the  seed-bearing 
plants  during  the  Mesozoic  era.  Ancestors  of  Arau- 
caria  must  have  been  common  trees  in  the  European 
vegetation  in  Jurassic  and  Lower  Cretaceous  periods, 
and  even  as  late  as  the  Tertiary  period  there  is  evidence 
that  representatives  of  the  family  still  lingered  in 
the  north.  One  conclusion  which  seems  almost  un- 
avoidable is  that  the  species  of  Araucaria  and  Agathis 
that  survive,  in  some  cases  only  in  one  or  two  small 
islands  in  the  South  Pacific,  have  in  the  course  of 
successive  ages  wandered  from  the  other  end  of  the 
world.  Their  migrations  can  be  partially  traced  by 
the  fragments  embedded  in  Jurassic  and  later  sedi- 
ments, but  we  can  only  speculate  as  to  the  causes 
which  have  contributed  to  the  changes  in  the  fortunes 
of  the  family ;  how  much  influence  may  have  been 
exerted  by  changes  in  physical  conditions  in  the 
environment,  and  to  what  extent  the  production  of 
more  successful  types  may  have  been  the  dominant 
cause  of  the  decline,  it  is  impossible  to  say.  One 
thing  at  least  is  certain,  that  few  existing  plants  are 
better  entitled  to  veneration  as  survivals  from  the 
past  than  are  the  living  species  of  Araucaria. 


CHAPTER  VIII 

THE   MAIDEN   HAIR  TREE 

'  ...the  trees 
That  whisper  round  a  temple  become  soon 
Dear  as  the  temple's  self.'     Keats. 

The  Maiden  Hair  tree  of  China  and  Japan,  which 
Avas  introduced  into  Europe  early  in  the  eighteenth 
century,  has  now  become  fairly  well  known.  Though 
hardy  in  England,  it  requires  warmer  summers  for 
full  development  and  regular  flowering.  To  botan- 
ists this  Eastern  tree  is  of  peculiar  interest,  partly 
because  of  the  isolated  position  it  occupies  in  the 
plant-kingdom  and  partly  by  reason  of  its  great 
antiquity.  There  is  probably  no  other  existing  tree 
which  has  so  strong  a  claim  to  be  styled  a  'living 
fossil,'  to  use  a  term  applied  by  Darwin  to  survivals 
from  the  past.  In  1/12  the  traveller  Kaempfer 
proposed  for  this  plant  the  generic  name  Ginkgo, 
and  Linnaeus  adopted  this  designation,  adding  the 
specific  name  biloha  to  denote  the  bisection  of 
the    wedge-shaped    lamina    of    the    leaf    into    two 


122 


LINKS  WITH  THE   PAST 


[CH. 


divergent  segments.     In  1777  the  English  botanist 
Sir  J.  E.  Smith  expressed  his  disapproval  of  what 


Fig.  19.     Ginkgo  biloha  Linn.     (Slightly  reduced.) 

he  called  the  uncouth  name  Ginkgo  by  substituting 
for  Ginkgo  biloha  the  title  Salisburia  adiantifoliaj 


VIII]  THE  MAIDEN  HAIR  TREE  123 

but  as  it  is  customary  to  retain  names  adopted  or 
proposed  by  Linnaeus,  the  founder  of  the  binominal 
system  of  nomenclature,  the  correct  botanical  desig- 
nation of  the  maiden  hair  tree  is  Ghikgo  hiloha. 
Mere  personal  preference  such  as  that  of  Sir  J.  E. 
Smith  for  Salisburia  is  not  an  adequate  reason  for 
rejecting  an  older  name. 

In  its  pyramidal  habit  Ginkgo  agrees  generally 
with  the  larch  and  other  Conifers.  Like  the  larch 
and  cedar  it  possesses  two  kinds  of  foliage  shoots, 
the  more  rapidly  growing  long  shoots  with  scattered 
leaves  and  the  much  shorter  dwarf-shoots  which 
elongate  slightly  each  year  and  bear  several  leaves 
crowded  round  their  apex.  The  leaves  (Fig.  19), 
which  are  shed  each  year,  are  similar  in  the  cuneate 
form  of  the  lamina  and  in  the  fan-like  distribution 
of  the  forked  veins,  to  the  large  leaflets  of  some 
species  of  maiden  hair  ferns  :  the  thin  lamina  carried 
by  a  slender  leaf-stalk  is  usually  about  3  inches 
across,  though  in  exceptional  cases  it  may  reach  a 
breadth  of  8  inches.  The  lamina  is  usually  divided 
by  a  deep  V-shaped  sinus  into  two  equal  halves  ; 
it  may  be  entire  with  an  irregularly  crenulate  margin, 
or,  on  seedlings  and  vigorous  long  shoots,  the  lamina 
may  be  cut  into  several  wedge-shaped  segments. 

The  male  and  female  flowers  are  borne  on  separate 
trees  ;  the  male  consists  of  a  central  axis  giving  off 
slender  branches,   each  of  which  ends  in  a  small 


124  LINKS   WITH   THE    PAST  [CH. 

terminal  knot  and  two  elliptical  capsules  in  which 
the  pollen  is  produced.  The  female  flowers  have 
a  stouter  axis  which  normally  produces  two  seeds 
at  the  apex.  The  seed  is  encased  in  a  green  fleshy 
substance  and,  as  in  the  fruit  of  a  cherry  or  plum, 
the  kernel  is  protected  by  a  hard  w^oody  shell.  In 
the  form  of  the  leaves  and  in  the  structure  of  the 
flowers  Ginkgo  presents  features  which  clearly  dis- 
tinguish it  from  the  Conifers,  the  class  in  w^hich, 
until  recently,  it  w^as  included.  In  1896  the  Japanese 
botanist  Hirase  made  the  important  discovery  that 
the  male  reproductive  cells  of  Ginkgo  are  large 
motile  bodies  provided  Avith  a  spirally  coiled  band 
of  minute  cilia — delicate  hairs  which  by  their 
rapid  lashing-movement  propel  the  cell  through 
water.  In  all  Flow ering  Plants  and  in  Conifers  the 
male  reproductive  cells  have  no  independent  means 
of  locomotion  ;  they  are  carried  to  the  female  cell 
by  the  formation  of  a  slender  tube — the  pollen-tube — 
produced  by  the  pollen-grain.  In  the  Ferns,  Lyco- 
pods  and  Horsetails — in  fact  in  all  members  of 
the  Pteridophyta — as  also  in  the  Mosses  and  Liver- 
worts as  well  as  in  many  of  the  still  lower  plants,  the 
male  cells  swim  to  the  egg  by  the  lashing  of  cilia 
like  those  on  the  male  cells  of  Ginkgo.  This  difference 
in  regard  to  the  nature  of  the  male  cells  was  con- 
sidered to  be  a  fundamental  distinction  between  the 
higher  seed-bearing  plants  and  all  other  groups  of 


VIII]  THE   MAIDEN  HAIR  TREE  125 

the  vegetable  kingdom.  It  was,  therefore,  with  no 
ordinary  interest  that  Hirase's  discovery  was  received, 
as  it  broke  down  a  distinction  between  the  two  great 
divisions  of  the  plant- world  which  had  been  generally 
accepted  as  fundamental ;  though  it  is  only  fair  to 
say  that  the  German  botanist  Hofmeister,  a  man  of 
exceptional  originality  and  power  of  grasping  the 
essential,  foresaw  the  possibility  that  this  arbitrary 
barrier  would  eventually  be  removed.  The  Ferns 
and  other  plants  in  which  the  male  cells  are  motile, 
represent  earlier  stages  in  the  progress  of  plant 
development,  when  the  presence  of  water  was  essen- 
tial for  the  act  of  fertilisation,  a  relic  of  earlier  days 
when  the  whole  plant-body  was  fitted  for  a  life  in 
water.  As  higher  types  were  produced,  the  plant- 
machinery  became  less  dependent  on  an  aqueous 
habitat,  and  the  loss  of  organs  of  locomotion  in  the 
male  cells  is  an  instance  of  the  kind  of  change 
accompanying  the  gradual  adaptation  to  life  on 
land.  The  idea  of  the  gradual  emancipation  of  plants 
from  a  watery  environment  is  expressed  in  a  some- 
what extreme  form  by  the  author  of  a  book  entitled 
The  Lessons  of  Evolution  (52),  who  states  that  the 
ocean  is  the  mother  of  plant-life  and  that  plants 
formed  the  army  which  conquered  the  land.  In 
Ginkgo  we  have  a  type  which,  though  similar  in 
most  respects  to  the  (.Conifers,  possesses  in  its  motile 
reproductive  cells  a  persistent  inheritance  from  the 


126  LINKS  WITH   THE   PAST  [cH. 

past.  The  recognition  of  this  special  feature  afforded 
a  sound  reason,  especially  when  other  peculiarities  are 
considered,  for  removing  Ginkgo  from  the  Conifers 
and  instituting  a  new  class-name,  Ginkgoales. 

Ginkgo  is  a  generalised  type,  linked  by  different 
characters  both  with  living  members  of  the  two  classes 
of  naked-seeded  plants  and  with  certain  existing 
Palaeozoic  genera.  It  is  a  survivor  of  a  race  which 
has  narrowly  escaped  extinction  ;  the  last  of  a  long 
line  that  has  outlived  its  family  and  offers  by  its  per- 
sistence an  impressive  instance  of  the  past  in  the 
present.  Though  Mrs  Bishop  in  her  Untrodden 
Patlis  in  Japan  speaks  of  forests  of  IMaiden  Hair 
trees  apparently  in  a  wild  state,  it  is  generally 
believed  that  they  were  cultivated  specimens. 
Mr  Henry  who  has  an  exceptionally  wide  knowledge 
of  Cliinese  vegetation  tells  us  that  'all  scientific 
travellers  in  Japan  and  the  leading  Japanese  botanists 
and  foresters  deny  its  being  indigenous  in  any  part  of 
Japan  ;  and  botanical  collectors  have  not  observed  it 
truly  wild  in  China.'  JNIoreover,  Mr  E.  H.  Wilson, 
after  traversing  the  whole  of  the  district  where 
Ginkgo  was  supposed  to  occur  in  a  wild  state,  says 
that  he  found  only  cultivated  trees.  There  is  no  reason 
to  doubt  that  China  is  the  last  stronghold  of  this 
ancient  type  which  in  an  earlier  period  of  the  earth's 
history  overspread  the  world. 

A  brief  summary  of  the  past  history  of  Ginkgo 


VIII]  THE   MAIDEN  HAIR  TREE  127 

and  of  the  Ginkgoales  supplies  overwhelming  testi- 
mony to  the  tenacity  of  life  with  which  the  INIaiden 
Hair  tree  has  persisted  through  the  ages. 

It  was  pointed  out  in  the  account  of  the  past 
history  of  Araucaria  that  the  records  obtained  from 
Palaeozoic  rocks,  while  affording  evidence  of  the 
existence  of  Carboniferous  and  Permian  genera  un- 
doubtedly allied  to  the  living  species,  do  not  enable 
us  to  speak  with  certainty  as  to  the  precise  degree  of 
affinity.  Similarly,  Palaeozoic  leaves  have  been  de- 
scribed as  representatives  of  the  class  of  which  Ginkgo 
is  the  sole  survivor,  but  the  evidence  on  which  this 
relationship  is  assumed  is  by  no  means  conclusive. 

The  generic  name  Psygmophyllum  has  been  applied 
to  some  impressions  of  Ginkgo-like  leaves  discovered 
in  the  Upper  Devonian  rocks  of  Bear  Island,  a  small 
remnant  of  land  in  the  Arctic  circle,  which  has  fur- 
nished valuable  information  as  to  the  composition  of 
one  of  the  oldest  floras  of  which  satisfactory  remains 
have  been  found.  Other  examples  of  these  lobed, 
wedge-shaped  leaves  are  recorded  fi'om  Carbonifer- 
ous rocks  in  Germany,  France,  and  elsewhere  ;  from 
Permian  strata  in  the  east  of  Russia  and  from  Palaeo- 
zoic beds  in  Cape  Colony  and  Kashmir.  A  relationship 
between  Psygmophyllum  and  Ginkgo  is,  however,  by 
no  means  established  and  rests  solely  on  a  resemblance 
in  the  form  of  the  leaves.  The  close  correspondence  in 
form  and  venation  between  some  leaves  from  Permian 


128  LINKS   WITH   THE   PAST  [ch. 

rocks  in  the  Ural  mountains  and  from  Lower  Permian 
beds  in  France,  and  those  of  the  recent  species,  is 
considered  by  some  authors  sufficiently  striking  to 
justify  the  reference  of  these  fossils  to  tlie  genus 
Ginkgo.  Similar  leaves  of  Permian  age,  which  may 
also  be  related  to  the  existing  species,  have  been 
described  under  the  name  Ginkgophyllum.  Other 
specimens  of  Palaeozoic  age  from  North  America 
and  elsewhere  have  been  assigned  to  the  Ginkgoales ; 
but  in  none  of  these  cases,  despite  the  resemblance 
in  leaf-form,  is  there  sufficiently  convincing  evidence 
of  close  relationship  to  warrant  a  definite  assertion 
that  the  plants  in  question  were  members  of  the 
group  of  which  Ginkgo  alone  remains. 

It  is,  however,  an  undoubted  fact  that  the  INIaiden 
Hair  tree  is  connected  by  a  long  line  of  ancestors 
with  the  earliest  phase  of  the  Mesozoic  era.  From 
many  parts  of  the  world  large  collections  of  fossil 
plants  have  been  obtained  from  strata  referred  to 
the  Rhaetic  period,  or  to  the  upper  division  of  the 
Triassic  system.  A  comparison  of  floras  from  these 
geological  horizons  in  different  parts  of  the  world 
points  to  a  vegetation  extending  from  Australia, 
Cape  Colony,  and  South  America,  to  Tonkin,  the  south 
of  Sweden  and  North  America,  which  Avas  character- 
ised by  a  greater  uniformity  than  is  shown  by  widely 
separated  floras  at  the  present  day.  One  of  the  com- 
monest genera   in  Rhaetic  floras  is  that  known  as 


VIII]  THE   MAIDEN   HAIR   TREE  129 

Baiera  ;  this  name  is  applied  to  wedge-shaped  leaves 
with  a  slender  stalk  similar  in  shape  and  venation  to 
those  of- Ginkgo,  but  differing  in  the  greater  number 
and  smaller  breadth  of  the  segments.     Between  the 
deeply  dissected   leaf  of  a  typical  Baiera  with   its 
narrow  linear  lobes  and  the  entire  or  broadly  lobed 
leaf  of  a  Ginkgo  there  are  many  connecting  links,  and 
to  some  specimens  either  name  might  be  applied  with 
equal  fitness.     Examples  of  Baiera  leaves,  in  some 
cases  associated  with  fragments  of  reproductive  organs, 
are  recorded  from  Rhaetic  rocks  of  France,  the  south 
of  Sweden,  Tonkin,  Chili,  the  Argentine,  Xorth  America, 
South  Africa,  and  from  other  regions.   There  is  abun- 
dant  evidence   pointing   to   the   almost   world-wide 
distribution  of  the  Ginkgoales,  as  represented  more 
especially  by  Baiera,  in  the  older  :\Iesozoic  floras.    In 
the  later  Jurassic  rocks  of  Yorkshire  true  Ginkgo 
leaves  as  well  as  those  of  the  Baiera  type  are  fairly 
common  ;   with  the  leaves  have  been  found  pieces 
of  male   and  female   flowers.     Ginkgo   and   Baiera 
have  been  described  from  Jurassic  rocks  of  Germany, 
France,  Russia,  Bornholm,  and  elsewhere  in  Europe  ; 
they  occur  abundantly  in  Middle  Jurassic  rocks  in 
northern  Siberia,  and  are  represented  in  the  Juras- 
sic floras  of  Franz  Josef  Land,  the  East  Coast  of 
Greenland,  and  Spitzbergen  (Fig.  20).     The  abund- 
ance  of  Ginkgo  and  Baiera  leaves  associated  with 
male  flowers  and  seeds  discovered  in  Jurassic  rocks, 

S.  a 


Fig.  20.     Fossil  Ginkgo  leaves.     (|  nat.  size.) 

A.  Tertiary,  Island  of  IMull. 

B.  Wealden,  North  Germany  (after  Schenk). 

C.  Jurassic,  Jajian  (after  Yokoyama). 

D.  Jurassic,  Australia  (after  Stirling). 

E.  Jurassic,  Siberia  (after  Heer). 

F.  Jurassic,  Turkestan. 

G.  Lower  Cretaceous,  Greenland  (after  Heer). 
H.  Jurassic,  California  (after  Fontaine). 

I.  Jurassic,  Yorkshire. 

J.  Jurassic,  N.E.  Scotland  (after  Stopes). 

K.  Wealden,  Franz  Josef  Land  (after  Nathorst). 

L.  Rhaetic,  South  Africa. 

M.  Jurassic,  Spitzbergen  (after  Heer). 


CH.  VIII]      THE  MAIDEN  HAIR  TREE  131 

approximately  of  the  same  geological  age  as  those  on 
the  Yorkshire  coast,  in  East  Siberia  and  in  the  Amur 
district,  has  led  to  the  suggestion  that  this  region 
may  have  been  a  centre  where  the  Ginkgoales  reached 
their  maximum  development  in  the  Mesozoic  period. 

It  should  be  added  that  other  genera  of  Jurassic 
and  Rhaetic  fossils  in  addition  to  Ginkgo  and  Baiera 
have  been  referred  to  the  Ginkgoales,  though  evidence 
of  such  affinity  is  not  convincing.  There  is,  however, 
good  reason  to  believe  that  this  Avidespread  group 
was  represented  by  several  genera  in  the  older  Meso- 
zoic floras. 

The  occurrence  of  the  Ginkgoales  in  Jurassic  rocks 
in  King  Charles  Land  and  in  the  Xew  Siberian  Islands 
(lat.  78°  and  75°  X.),  in  Central  China,  Japan, 
Turkestan,  California,  Oregon,  South  Africa,  Australia, 
and  Graham's  Land  demonstrates  the  cosmopolitan 
nature  of  the  group.  During  the  later  part  of  the 
Jurassic  period  and  in  the  Wealden  floras  both  Baiera 
and  Ginkgo  were  abundant ;  leaves  are  recorded  from 
Jurassic  strata  in  the  north-east  of  Scotland,  from 
Lower  Cretaceous  or  Wealden  rocks  in  North  Germany, 
Portugal,  Vancouver  Island,  Wyoming,  and  Greenland. 

During  the  Tertiary  period,  or  probably  in  the 
earlier  days  of  that  era.  Ginkgo  flourished  in  North 
America,  in  Alaska  and  in  the  jNIackenzie  River  district, 
Greenland,  Saghalien  Island,  and  in  several  European 
regions.     In  Chapter  III  reference  was  made  to  the 

9-2 


132  LINKS   WITH   THE   PAST  [ch. 

volcanic  activity  which  characterised  the  north-west 
European  area  in  the  early  Tertiary  period  and  resulted 
in  the  formation  of  the  thick  sheets  of  basalt  on  the 
north-east  coast  of  Ireland  and  in  the  Inner  Hebrides. 
There  were  occasional  pauses  in  the  volcanic  activity, 
during  which  vegetation  established  itself  on  the 
wreath ered  surface  of  the  lava,  and  left  traces  of  its 
existence  in  the  leaves  and  twigs  preserved  in  the 
sedimentary  material  enclosed  between  successive 
lava-floras.  xVt  Ardtun  Head  in  the  Isle  of  Mull 
beautifully  preserved  leaves  of  Ginkgo,  2 — 4  inches 
in  breadth,  with  the  median  sinus  and  the  venation 
characteristic  of  the  leaves  of  the  existing  plant,  have 
been  discovered  in  a  bed  of  clay  which  marks  the  site 
of  a  lake  in  a  depression  on  the  lava-plateau.  The 
resemblance  of  these  Tertiary  leaves  fi-om  Mull  to 
those  of  the  surviving  Maiden  Hair  tree  is  so  close  as 
to  suggest  specific  identity.  Mr  Starkie  Gardner  and 
Baron  Ettingshausen  have  described  some  seeds  from 
the  London  clay  (Lower  Tertiary)  in  the  Isleof  Sheppey 
as  those  of  Ginkgo,  but  this  identification  rests  on 
data  too  insufficient  to  be  accepted  without  hesitation. 
The  recent  cultivation  of  Ginkgo  hiloha  in  Britain 
may  therefore  be  spoken  of  as  the  re-introduction  of 
a  plant  which  in  the  earlier  part  or  in  the  middle  of 
the  Tertiary  period  flourished  in  the  west  of  Scotland, 
and  was  abundant  in  England  in  the  earlier  Jurassic 
period.  It  is  impossible  to  say  with  any  confidence 
where  the  Ginkgoales  first  made  their  appearance. 


VIII]  THE   MAIDEN   HAIR   TREE  133 

whether  in  the  far  north  or  in  the  south,  nor  are  we 
able  to  explain  the  gradual  decline  of  so  venerable 
and  vigorous  a  race. 

As  we  search  among  the  fragmentary  herbaria 
scattered  through  the  sedimentar}^  rocks  in  that  com- 
paratively small  portion  of  the  earth's  crust  which  is 
accessible  to  investigation,  we  discover  evidence  of 
a  shifting  of  the  balance  of  power  among  diiFerent 
classes  of  plants  in  the  course  of  our  survey  of  suc- 
cessive floras.  Plants  now  insignificant  and  few  in 
number  are  found  to  be  descendants  of  a  long  line  of 
ancestors  stretching  back  to  a  remote  antiquity  when 
they  formed  the  dominant  class.  Others  which  flour- 
ished in  a  former  period  no  longer  survive,  either 
themselves  or  in  direct  descendants.  '  The  extinction 
of  species  has  been  involved  in  the  most  gratuitous 
mystery.'  We  can  only  speculate  vaguely  as  to  the 
cause  of  success  or  failure.  Certain  types  were  better 
armed  for  the  struggle  for  life,  and  produced  de- 
scendants able  to  hold  their  own  and  to  perpetuate 
the  race  through  the  ages  in  an  unbroken  line. 
Others  had  a  shorter  life  and  fell  out  of  the  ranks  of 
the  advancing  and  ever  changing  army.  To  quote 
Darwin's  words  :  '  We  need  not  marvel  at  extinction ; 
if  we  must  marvel,  let  it  be  at  our  own  presumption 
in  imagining  for  a  moment  that  we  understand  the 
many  complex  contingencies  on  which  the  existence 
of  each  species  depends.' 


BIBLIOGRAPHY 

Many  of  the  books  and  papers  dealing  with  subjects  touched 
upon  in  this  vohinie  are  not  inchided  in  the  following-  list.  For 
reference  to  a  more  complete  bibliography  the  reader  should 
consult  more  technical  treatises. 

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multidens.     Bull.  Soc.  Beige  de  Geol.  etc..  Tome  iv. 
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1909. 

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and  its  significance.     New  Phytologist^  Vol.  vi.  p.  203. 
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INDEX 


Aachenosaurus  multidens,  68 

Agathis  australis,  107 

A.  Moorei,  108 

A.  robusta,  108,  109 

Amber,  65,  66 

Amethyst  Mountain,  59,  60,  104 

Amundsen,  E.,  62 

Aiiacharis  alsuiastrum,  20 

Angiosperms,  histoiy  of,  16,  53, 

69,  70 
Annual  rings,  5-9 
Antarctic  fossil  plants,  70,  117 
Araucaria  Bidivillii,  115 
A.  hrasiliana,  109 
A.  Cookii,  111,  118 
A.    excelsa,    110,   111,    lU,    115, 

118 
A.  imbricata,  109,  111,  113,  118 
Araucarieae,  106-120 
Araucarioxylon,  112 
Araucarites  Oldhami,  113 
A.  sphaerocarpus,  116 
Arbutus  Unedo,  31-33,  36 
Archaean  rocks,  43 
Arctic  plants,  22,  23,  30,  69,  127 
Arctic-Alpine  plants,  22,  23 
Arizona,  fossil  forests  of,  59 
Artocarpus,  28,  29 

Baiera,  129,  131 
Banks,  Sir  Joseph,  110 
Barry,  forest  beds  at,  13 


Bennett,  A. ,  21 

Bidens  trqHirtita,  46,  47 

Bishop,  Mrs,  126 

Bommer,  C,  73,  82,  89 

Bovey  Tracev,  fossil  plants  from, 

loi-103 
Bower,  Prof.,  73 
Bracken  Fern,  75,  77,  83,  87' 
Brandon,  flint-knappers  of,  3 
Brigg,  dug-out  boat  from,  10,  11 
British  flora,  19-38 

Caltha  palustris,  47 
Campbell,  Prof.  D.  H.,  79 
Candolle,  A.  P.  de,  7,  33 
Canton,  W.,  34 
Carboniferous  plants,  66-68,  72- 

75,  127 
Carruthers,  Dr  W.,  115 
Cedars,  27 
Cheddar  Pink,  24 
C  inn  a  mo  mum  prototypum,  65,  66 
Climate,  fossil  plants  and,  68,  69 
Coal  lage,  plants  of  the,  19,    66, 

67 
Connemara,  30,  31 
Cook,  Capt.,  Ill 
Coral  polyps  compared  with  plants, 

8 
Cordaites,  112 
Cornwall,    Pyrenean   Heaths   in, 

31 


140 


INDEX 


Cretaceous  plants,  16,  17,  53,  82, 

117 
Cromer  Forest  bed,  48 
Cryptomeria  japonica,  111 
Cycads,  11,  72-74 

Daboecia  polifolia,  30 

Dacrvdium,  85 

Dakota  Ki^oup,  flora  of,  17 

Dammara  alba,  107 

Darwin,  C,  16,  24,  25,  33,  39,  40, 

61,  133 
Devonshire,  Pyrenean  Heaths  in, 

31 
Dianthus  caesius,  24 
Dipteris,  77,  92-94 
I),  conjugata,  92,  93 

D.  Horsneldii,  86,  93 

Disco  Island,  Fossil  plants  from, 

28,  69,  82,  103 
Discontinuous  distribution,  26 
Dispersal  of  plants,  rate  of,  25,  26 
Distribution  of  plants,  15-38 
Drift-wood,  61-63 
Dry  as  octopetala,  22 
Dufferin,  Lord,  61 

Elodea  canadensis,  20,  21 
Engler,  Prof. ,  23 
Erica  ci  liar  is,  31 

E.  Mackaii,  31 

E.  mediterranea,  30,  31 

E.  vagans,  31 

EriocauJon  septangnlare,  35-38 

Ettingshausen,  Baron,  105,  132 

Ferns,  71-94 

Flowering     plants,     see     Angio- 

sperms 
Forbes,  E.,  31-34,37 
Fossil  plants,  as  thermometers, 

68;  preservation  of,  56-70 


Gardner,  J.  S.,  132 

Geogi'aphical  distribution  of 
plants,  15-38 

Geological  evolution  of  Britain, 
29 

Geological  record,  39-55 

Geological  table,  42,  43 

Geological  time,  2,  3,  49 

Ginkqo  biloba,  113,  120-133 

Ginkgoales,  18,  120-133 

Ginkgophyllum,  128 

Glacial  period,  effect  on  vege- 
tation of,  29-32,  45,  47 

Gladiolus  illi/riciis,  31 

Gleichenia,  81-83 

Graham's  Land,  70,  117 

Gunn,  Dr  Marcns,  117 

Gwynue-Vaughan,  Prof.,  80 

Gymnosperms,  17,  18 

Habenaria  intacta,  37 

Halifax,  plants  from  canal  near, 

21 
Heer,  0.,33,  82,  101 
Henry,  A.,  126 
Hirase,  Prof.,  124,  125 
Hofmeister,  W.  F.  B.,  125 
Hollick,  A.,  119 
Holmes,  T.  Kice,  2 
Hooker,   Sir  J.  D.,  4,  15,  16,  22, 

23,  27,  40 
Hose,  C,  87 
Huxley,  T.  H.,  11,  52 

Ireland,  Mediterranean  plants  in, 
30-38 

Jeffrey,  Prof.  E.  C,  114,  119 
Jet,  114 

Juan  Fernandez,  84 
Jurassic  flora,  53,  54,  70,  117 
Jussieu,  A.  de,  109 


INDEX 


141 


Kaempfer,  E.,  121 
Kauri  Piue,  107 
Kidston,  Dr  E.,  74,  80 
Knaresborongh,  petrifying  spring 

at,  (U 
Krakatau,  new  flora  of,  33,  31 

Laccopteris,  90,  91 
Lang,  Dr  A. ,  27 
Lankester,  Sir  Edwin  Eay,  49 
Lhywd,  E.,  57 
Linnaeus,  C,  121,  123 
Liriodendron,  28,  29 
Liverworts,  antiquity  of,  79 
London  Pride,  31 
Longevity  of  trees,  1-10 
Liizula  racemosa,  23 
L.  spicata,  23,  24 

MacDougal,  Prof.,  62 

Maiden  Hair  Tree,  120-133 

Mammoth  trees  of  California, 
95-105 

Man,  first  appearance  of,  49 

Marchantia,  79 

Market  Harborough,  Elodea  dis- 
covered near,  20 

Marshall,  E.  S.,  38 

Matonia,  77,  86-94 

M.  pectiiiata,  86-88,  92,  93 

M.  sannentosa,  87 

Matonidium,  89 

Mediterranean  plants  in  Ireland, 
30-38 

Miller,  Hugh,  59,  115,  117 

Milligan,  Dr,  2 

Moss,  Dr  C.  E.,  23 

Mull,  Fossil  plants  in  Isle  of,  132 

Naias  gr  amine  a,  21 
Nathorst,  A.  G.,  64,  103,  117 
Native  plants,  20 


New  forest,  31 
Nipafruticans,  50-52 
Nipadites,  50,  52 
Norfolk  Island  Pine,    see  Arau- 
caria  excelsa 

Oaks,  longevitv  of,  4 
Oliver,  Prof.  F.  W.,  74 
Osmunda  regalis,  76-79,  83 
Osmundites  Dunlopi,  80 

Palaeozoic  plants,  55,  66-68,  71, 

127,  128 
Peat,  trees  in,  12,  13 
Permian  floras,  55 
Petrifaction,  64-67 
Picea  excelsa,  46,  48 
Pines,  Tertiary,  65,  66 
Pinus  sylvestris,  11-13,  47 
Pipewort,  36-38 
Pliny's  Natural  History,  4 
Podocarpus,  109 
Potamogeton  pennsylv aniens,  21 
Praeger,  E.  L.,  32,  36,  37 
Pre-Glacial  plants,  22,  45-48 
Primula  elatior,  24 
Protodanimara,  119 
Psygmophyllum,  127 
Pteridium  aquilinum,  75,  77,  83, 

87 
Pteridophyta,  18,  124 
Pteridosperms,  74,  75 
Pyreneau  plants  in  Ireland,  31-38 

Kay,  John,  56 

Reddish  Canal,  plants  from  the, 

21 
Eedwoods  of  California,  95-105 
Eeid,  Clement,  13,  22,  45,  102 
Eeid,  Mrs,  22,  102 
Ehaetic  plants,  54,  94 
Riccia,  79 


142 


INDEX 


Kidley,  H.  N.,  25 
Royal  Fern,  76-79,  83 
Rubus  chamaentoriis,  22 

St  Dabeoc's  Heath,  30,  32,  37 

Salishuria  adiantifolia,  122 

Saporta,  the  Marquis  of,  70 

Saxifra(ja  oppositifolia,  22 

S.  Kinbrosa,  31 

Scandinavian  plants  in  Britain, 

21-23,  30 
Scots  Pine,  see  Pi)ius  sylre-^tris 
Scott,  Dr  D.  H.,  74 
Sequoia,  5,  95-105 
Sequoia  Couttsiae,  101 
S.  gigantea,  5,  95,  96,  98-104 
S.  magnifica,  104 
S.  novae  zeelandlcae,  105 
S.  semperviretis,  45,  96,  98,  104 
Sheppey,  fossil  plants  from,  50, 

132 
Shorea  leprosula,  25 
Silene  acaulis,  22 
Sisgriiichium  angiistifoUiim,  38 
S.  californicuni,  38 
Smith,  G.,  75 
Smith,  Sir  J.  E.,  122,  123 
Smith,  W.,  41 
Sollas,  Prof.,  58 
Spiranthes  romanzojjiana,  38 
Stellaria  holostea,  4(i,  47 
Steno,  57 


Strahan,  A.,  13 
Strawberry  tree,  31,  32 

Tansley,  A.  G.,  12,  13,  87 
Taxodium  distichwn,  103 
Tertiary  plants,    31-33,   37,    49, 

50,  103 
Theobroma  cacao,  7 
Thyrsopteris  elegans,  84 
Todea  harbara,  11,1^ 
T.  r ad i cans,  78 
Trapa  natans,  47,  48 
Triassic  period,  54,  55 
Tulip  tree,  28 

Walchia,  113 

Wallace,  Dr  A.  R.,  85 

Wealden  flora,  17,  53 

Weismann,  A.,  3 

Wexford,  American  plant  from,  38 

Williamson,  Prof.  W.  C,  72 

Wilson,  E.  H.,  120 

Winchester  Cathedral,  wood  from 

foundations  of,  10 
Woodward,  Dr  J.,  57 
Woodworthia,  114 

Yellowstone  Park,  fossil  trees  in 
the,  59-61,  104 

Zeiller,  E.,  113 


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New  Zealand.     By  the  Hon.  Sir  Robert  Stout,  K.C.M.G.,  LL.D., 

and  J.  Logan  Stout,  LL.B.  (N.Z.). 
King  Arthur  in  History  and  Legend.     By  Prof.  W.  Lewis  Jones, 

M.A. 
The  Early  Religious  Poetry  of  Persia.     By  the  Rev.  Prof.  J.  Hope 

Moulton,  D.D.,  D.Theol.  (Berlin). 
Greek  Tragedy.     By  J.  T.  Sheppard,  M.A. 
The  Wanderings  of  Peoples.     By  Dr  A.  C.  Haddon,  F.R.S. 
Links  with  the  Past  in  the  Plant- World.     By  Prof.  A.  C.  Seward, 

F.R.S. 
Primitive  Animals.     By  Geoffrey  Smith,  M.A. 
Life  in  the  Sea.     By  James  Johnstone,  B.Sc. 

The  Moral  Life  and  Moral  Worth.     By  Prof.  Sorley,  Litt.D.,  F.B.A. 
The  Migration  of  Birds.     By  T.  A.  Coward. 
Earthworms  and  their  Allies.     By  F.  E.  Beddard.  M.A.,  F.R.S. 
Prehistoric  Man.     By  Dr  W.  L.  H.  Duckworth. 
The  Modern  Locomotive.     By  C.  Edgar  Allen,  A.M.I. Mech.E. 
The  Natural  History  of  Clay.     By  Alfred  B.  Searle. 


VOLUMES  IN  PREPARATION 


Ancient  Assyria.     By  Rev.  C.  H.  W.  Johns,  Litt.D. 

The  Civilization  of  Ancient  Mexico.     By  Lewis  Spence. 

Clouds.     By  C.  T.  R.  Wilson.  F.R.S. 

The  Work  of  Rain  and  Rivers.     By  the  Rev.  Prof.  T.  G.  Bonney 

LL.D.,  ScD.,  F.R.S. 
Rocks  and  their  Origin.     By  Prof.  Grenville  A.  J.  Cole. 


VOLUMES  IN  PREPARATION  (continued) 

The  Measurement  of  Time,     By  the  Astronomer  Royal. 

St  Paul  and  Christianity.     By  the  Rev.  Principal  Headlam,  D.D. 

The  Development  of  Coinage.     By  George  Macdonald,  LL.D. 

The  Origin  of  Earthquakes.     By  Dr  C.  Davison. 

A  History  of  Civilisation  in  Palestine.    By  Prof.  R.  A.  S.  Macalister, 

M.A.,  F.S.A. 
Glaciers  and  Ice  Sheets.     By  Prof.  Garwood,  M.A.,  Sec.G.S. 
Goethe  in  the  Twentieth  Century.    By  Prof.  J.  G.  Robertson,  M.A., 

Ph.D. 
The  Psychology  of  Insanity.     By  Dr  Bernard  Hart. 
The  New  Field  Botany.     By  Dr  C.  E.  Moss. 
Spiders.     By  C.  Warburton,  M.A. 
Flies.     By  Dr  Gordon  Hewitt. 
The  Green  Leaf.     By  Dr  F.  F.  Blackman,  F.R.S. 
The  Phoenicians.     By  Prof.  J.  L.  Myres,  F.S.A. 
The  Physical  Basis  of  Music.     By  A.  Wood,  M.A. 
The  Meteorology  of  the  Globe.     By  Dr  W.  N.  Shaw,  F.R.S. 
Brewing.     By  A.  Chaston  Chapman,  F.I.C. 
The  Talmud.     By  I.  Abrahams,  M.A. 

Growth  and  Form.     By  Prof.  D'Arcy  W.  Thompson,  C.B.,  M.A. 
Beyond  the  Atom.     By  Prof.  J.  Cox. 
The  Early  History  of  India.     By  E.  J.  Rapson,  M.A. 
Methodism.     By  Rev.  H.  B.  Workman,  D.Lit. 
The  Ballad  in  Literature.     By  T.  F.  Henderson. 
Life  in  the  Medieval  University.     By  R.  S.  Rait.  M.A. 
The  Icelandic  Sagas.     By  W.  A.  Craigie,  LL  D. 
Mysticism    in    Modern    English    Literature.       By    Miss   C.    F.    E. 

Spurgeon. 
The  Early  Religious  Poetry  of  India.     By  A.  A.  Macdonell. 
German  School  Education.     By  K.  H.  Breul,  Litt.D. 
The  Moral  and  Political  Ideas  of  Plato.     By  A.  M.  Adam,  M.A. 
The  Growth  of  Municipalities.     By  H.  D.  Hazeltine,  M.A 
Ancient  Babylonia.     By  Rev.  C.  H.  W.  Johns,  Litt.D. 
Early  Christian  Poetry.     By  F.  C.  Burkitt,  M.A..  F.B.A. 
Discovery  in  Greek  Lands.     By  F.  H.  Marshall,  M.A. 
The  Poetry  of  Burns.     By  H.  J.  C.  Grierson,  M.A. 
The  Crusades.     By  Rev.  Prof.  J.  P.  Whitney.  B.D. 


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